Retirement Benefits [Abstract] Retirement Plans Pension and Other Postretirement Benefits Disclosure [Text Block] Derivative Instruments and Hedging Activities Disclosure [Abstract] Derivative [Table] Derivative [Table] Hedging Relationship Hedging Relationship [Axis] Hedging Relationship Hedging Relationship [Domain] Cash Flow Hedging Cash Flow Hedging [Member] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name Debt Instrument, Name [Domain] Interest rate swaps 1 Interest Rate Swap, Number One [Member] Interest Rate Swap, Number One [Member] Interest rate swaps 2 Interest Rate Swap, Number Two [Member] Interest Rate Swap, Number Two [Member] Interest rate swaps 3 Interest Rate Swap, Number Three [Member] Interest Rate Swap, Number Three [Member] Interest rate swaps 4 Interest Rate Swap,Number Four [Member] Interest Rate Swap,Number Four [Member] Interest rate swaps 5 Interest Rate Swap, Number Five [Member] Interest Rate Swap, Number Five [Member] Derivative Instrument Derivative Instrument [Axis] Derivative Contract Derivative Contract [Domain] Interest Rate Swaps Interest Rate Swap [Member] Derivative [Line Items] Derivative [Line Items] Notional Amount Derivative, Notional Amount Pay Fixed Rate Derivative, Fixed Interest Rate Receive Variable Rate Debt Instrument, Description of Variable Rate Basis Settlement and Termination Derivative Contract Settlement And Termination Derivative contract settlement and termination. Asset (Liability) Fair Value Derivative Assets (Liabilities), at Fair Value, Net Derivative, cash received on hedge Derivative, Cash Received on Hedge Accumulated other comprehensive income loss cumulative Changes In Net Gain Loss From Cash Flow Hedges Effect Before Tax1 Accumulated Other Comprehensive Income Loss Cumulative Changes In Net Gain Loss From Cash Flow Hedges Effect Before Tax1 Accumulated other comprehensive income loss cumulative changes in net gain loss from cash flow hedges effect before tax 1. Derivative instrument floor rate Derivative, Floor Interest Rate Property, Plant and Equipment [Abstract] Property, Plant, and Equipment Property, Plant and Equipment Disclosure [Text Block] Goodwill and Intangible Assets Disclosure [Abstract] Goodwill Goodwill Increase in goodwill Goodwill, Period Increase (Decrease) Impairment of goodwill Goodwill, Impairment Loss Amortization expense related to intangible assets Amortization of Intangible Assets Intangible asset impairment losses Impairment of Intangible Assets, Finite-lived Income Tax Disclosure [Abstract] Income Taxes Income Tax Disclosure [Text Block] Derivative Instruments Designated as Cash Flow Hedges Schedule of Derivative Instruments [Table Text Block] Depreciation and amortization expense Depreciation, Depletion and Amortization Disclosure of Compensation Related Costs, Share-based Payments [Abstract] Stock-Based Compensation Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Equity [Abstract] Changes in Accumulated Other Comprehensive Loss by Component Comprehensive Income (Loss) Note [Text Block] Cash received from exercises of stock options Proceeds from Stock Options Exercised Stock exchanged at fair value upon exercises of stock options Stock Cancelled To Cover Price Of Options Exercises Stock cancelled to cover price of options exercises. Tax benefits from exercises of stock options Employee Service Share-based Compensation, Tax Benefit from Exercise of Stock Options Total intrinsic value of options exercised Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value Provision for Income Taxes Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] Reconciliation of Provision for Income Taxes Computed by Statutory Federal Income Tax Rate Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Deferred Tax Assets and Liabilities Schedule of Deferred Tax Assets and Liabilities [Table Text Block] Changes in Unrecognized Tax Benefits Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block] Statement of Financial Position [Abstract] ASSETS Assets [Abstract] Current assets: Assets, Current [Abstract] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Receivables, net (Note 3) Accounts Receivable, Net, Current Inventories, net Inventory, Net Prepaid expenses Prepaid Expense, Current Other current assets Other Assets, Current Total current assets Assets, Current Goodwill (Note 5) Intangible assets, net (Note 5) Finite-Lived Intangible Assets, Net Property, plant, and equipment, net (Note 6) Property, Plant and Equipment, Net Other assets Other Assets, Noncurrent Total assets Assets LIABILITIES AND EQUITY Liabilities and Equity [Abstract] Current liabilities: Liabilities, Current [Abstract] Accounts payable Accounts Payable, Current Accrued payroll and other employee benefits Other Employee-related Liabilities, Current Accrued vacation Accrued Vacation, Current Other accrued liabilities Other Accrued Liabilities, Current Long-term debt, current portion (Note 10) Long-term Debt, Current Maturities Total current liabilities Liabilities, Current Long-term debt, net of current portion (Note 10) Long-term Debt, Excluding Current Maturities Deferred income taxes Deferred Income Tax Liabilities, Net Other long-term liabilities Other Liabilities, Noncurrent Commitments and contingencies (Note 15) Commitments and Contingencies Equity: Stockholders' Equity Attributable to Parent [Abstract] Common stock, $.0001 par value, 1 billion shares authorized, 60 million shares and 43 million shares issued and outstanding as of February 1, 2019 and February 2, 2018, respectively Common Stock, Value, Issued Additional paid-in capital Additional Paid in Capital, Common Stock Retained earnings Retained Earnings (Accumulated Deficit) Accumulated other comprehensive (loss) income Accumulated Other Comprehensive Income (Loss), Net of Tax Total common stockholders' equity Stockholders' Equity Attributable to Parent Non-controlling interest Stockholders' Equity Attributable to Noncontrolling Interest Total stockholders' equity Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Total liabilities and stockholders' equity Liabilities and Equity Shares of stocks under stock options Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Outstanding, beginning balance (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Options granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures Options forfeited or expired (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period Options exercised (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Outstanding, ending balance (in shares) Options exercisable, ending balance (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number Options vested and expected to vest, ending balance (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number Weighted average exercise price Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] Outstanding beginning balance (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Options granted (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price Options forfeited or expired (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price Options exercised (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Outstanding ending balance (in dollars per share) Options exercisable (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price Vested and expected to vest in the future (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Exercise Price Weighted average remaining contractual term Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract] Outstanding Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term Options exercisable Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term Vested and expected to vest Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Weighted Average Remaining Contractual Term Aggregate intrinsic value Share Based Compensation Arrangement By Share Based Payment Award Options Aggregate Intrinsic Value [Abstract] Share based compensation arrangement by share based payment award options aggregate intrinsic value. Options outstanding Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value Options exercisable Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value Vested and expected to vest Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Aggregate Intrinsic Value Changes in Accumulated Other Comprehensive Income Attributable to the Company's Fixed Interest Rate Swap Cash Flow Hedges Schedule of Cash Flow Hedges Included in Accumulated Other Comprehensive Income (Loss) [Table Text Block] Segment Reporting [Abstract] Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Concentration Risk Benchmark Concentration Risk Benchmark [Axis] Concentration Risk Benchmark Concentration Risk Benchmark [Domain] Sales Revenue, Net Sales Revenue, Net [Member] Concentration Risk Type Concentration Risk Type [Axis] Concentration Risk Type Concentration Risk Type [Domain] Customer Concentration Risk Customer Concentration Risk [Member] Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Number of operating segments Number of Operating Segments Number of reportable segments Number of Reportable Segments Percentage of sales Concentration Risk, Percentage Quarterly Financial Information Disclosure [Abstract] Selected Quarterly Financial Data (Unaudited) Quarterly Financial Information [Text Block] Statement of Cash Flows [Abstract] Cash flows from operating activities: Net Cash Provided by (Used in) Operating Activities, Continuing Operations [Abstract] Net income (loss) Net Income (Loss) Attributable to Parent Adjustments to reconcile net income to net cash provided by operating activities: Adjustments, Noncash Items, to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation and amortization Depreciation, Depletion and Amortization, Nonproduction Deferred income taxes Deferred Income Taxes and Tax Credits Stock-based compensation expense Share-based Compensation Excess tax benefits from stock-based compensation Excess Tax Benefit from Share-based Compensation, Operating Activities Loss on disposal of property, plant, and equipment Gain (Loss) on Disposition of Property Plant Equipment Loss on extinguishment of debt Gain (Loss) on Extinguishment of Debt Provisions for inventory and deferred contract costs Inventory, Firm Purchase Commitment, Loss and Deferred Contract Costs Inventory, Firm Purchase Commitment, Loss and Deferred Contract Costs Increase (decrease) resulting from changes in operating assets and liabilities, net of the effect of the acquisition: Increase (Decrease) in Operating Capital [Abstract] Receivables Increase (Decrease) in Accounts Receivable Inventory, prepaid expenses, and other current assets Increase (Decrease) in Prepaid Expense and Other Assets Other assets Increase (Decrease) in Other Noncurrent Assets Accounts payable and accrued liabilities Increase (Decrease) in Accounts Payable and Accrued Liabilities Accrued payroll and employee benefits Increase (Decrease) in Employee Related Liabilities Other long-term liabilities Increase (Decrease) in Other Noncurrent Liabilities Net cash provided by operating activities Net Cash Provided by (Used in) Operating Activities Cash flows from investing activities: Net Cash Provided by (Used in) Investing Activities [Abstract] Expenditures for property, plant, and equipment Payments to Acquire Property, Plant, and Equipment Other Payments for (Proceeds from) Other Investing Activities Cash paid for acquisition, net of cash acquired Payments to Acquire Businesses, Net of Cash Acquired Net cash used in investing activities Net Cash Provided by (Used in) Investing Activities Cash flows from financing activities: Net Cash Provided by (Used in) Financing Activities [Abstract] Dividend payments to stockholders Payments of Ordinary Dividends, Common Stock Principal payments on borrowings Repayments of Debt Issuances of stock Proceeds from Issuance of Common Stock Stock repurchased and retired or withheld for taxes on equity awards Payments for Repurchase of Common Stock Excess tax benefits from stock-based compensation Excess Tax Benefit from Share-based Compensation, Financing Activities Disbursements for obligations assumed from Scitor acquisition Disbursements For Obligations Assumed From Acquisition Disbursements for obligations assumed from acquisition. Proceeds from borrowings Proceeds from Issuance of Debt Debt issuance costs Payments of Debt Issuance Costs Equity issuance costs Payments of Stock Issuance Costs Contributions from non-controlling interest Proceeds from Noncontrolling Interests Net cash provided by (used in) financing activities Net Cash Provided by (Used in) Financing Activities Net increase (decrease) in cash, cash equivalents and restricted cash Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Cash, cash equivalents and restricted cash at beginning of period Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Cash, cash equivalents and restricted cash at end of period (Note 1) Supplementary cash flow disclosure: Supplemental Cash Flow Information [Abstract] Cash paid for interest Interest Paid, Excluding Capitalized Interest, Operating Activities Cash paid for income taxes Income Taxes Paid Non-cash investing and financing activities: Noncash Investing and Financing Items [Abstract] Increase (decrease) in accrued plan share repurchases Increase Decrease In Accrued Plan Share Repurchases Increase (decrease) in accrued plan share repurchases. (Decrease) increase in accrued plant, property, and equipment Decrease In Capital Expenditures Incurred But Not Yet Paid Decrease in capital expenditures incurred but not yet paid. Fair value of equity consideration paid for acquisition Stock Issued Stock-Based Compensation and Related Tax Benefits Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan [Table Text Block] Stock Option Activity Share-based Compensation, Stock Options, Activity [Table Text Block] Schedule of Share-Based Compensation Activity Related to Exercise of Stock Options Schedule Of Share Based Compensation Activity Related To Exercise Of Stock Options Table [Text Block] Schedule of share based compensation activity related to exercise of stock options. Weighted Average Grant Date Fair Value and Assumptions Used to Determine Fair Value of Stock Options Granted Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block] Vesting Stock Award Activity Schedule of Unrecognized Compensation Cost, Nonvested Awards [Table Text Block] Performance Share Award Activity Share-based Compensation, Performance Shares Award Nonvested Activity [Table Text Block] Accounting Policies [Abstract] Business Overview and Summary of Significant Accounting Policies Organization, Consolidation and Presentation of Financial Statements Disclosure and Significant Accounting Policies [Text Block] Business Combinations [Abstract] Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree Business Acquisition, Acquiree [Domain] Engility Holdings, Inc Engility Holdings, Inc [Member] Engility Holdings, Inc [Member] Business Acquisition [Line Items] Business Acquisition [Line Items] Cash and cash equivalents Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents Receivables Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables Inventories Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Inventory Prepaid expenses Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets Other current assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Other Property, plant, and equipment Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment Deferred tax assets Business Combination Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Assets Other assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets Intangible assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill Total assets acquired Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets Including Goodwill Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets Including Goodwill Accounts payable Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Accounts Payable Accrued payroll and other employee benefits Business Combination Recognized Identifiable Assets Acquired And Liabilities Assumed Current Liabilities Accrued Payroll And Employee Benefits Business combination recognized identifiable assets acquired and liabilities assumed current liabilities accrued payroll and employee benefits. Accrued vacation Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities, Accrued Vacation Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities, Accrued Vacation Other accrued liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities, Other Accrued Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities, Other Accrued Other long-term liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Other Total liabilities assumed Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities Non-controlling interest Business Combination, Acquisition of Less than 100 Percent, Noncontrolling Interest, Fair Value Net assets acquired Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest Amount of tax deductible goodwill Business Acquisition, Goodwill, Expected Tax Deductible Amount Earnings Per Share [Abstract] Earnings Per Share, Share Repurchases and Dividends Earnings Per Share [Text Block] Revenue from Contract with Customer [Abstract] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table] Performance Period [Axis] Performance Period [Axis] Performance Period [Axis] Performance Period [Domain] Performance Period [Domain] [Domain] for Performance Period [Axis] Next Twelve Months Next Twelve Months [Member] Next Twelve Months [Member] Next Twenty Four Months Next Twenty Four Months [Member] Next Twenty Four Months [Member] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] Revenue, remaining performance obligation, percentage Revenue, Remaining Performance Obligation, Percentage Revenue, remaining performance obligation, expected timing of satisfaction, period Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period Statement of Comprehensive Income [Abstract] Net income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Other comprehensive (loss) income, net of tax: Other Comprehensive Income (Loss), Net of Tax [Abstract] Unrealized (loss) gain on derivative instruments, net of tax benefit (expense) of $6 million, $(2) million and $(1) million for the year ended February 1, 2019, February 2, 2018 and February 3, 2017, respectively Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, after Tax Reclassification adjustment for (benefits) costs realized in net income, net of tax expense (benefit) of $0 million, $(1) million and $(3) million for the year ended February 1, 2019, February 2, 2018 and February 3, 2017, respectively Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax Net unrealized (loss) gain on derivative instruments Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax Total other comprehensive (loss) income, net of tax Other Comprehensive Income (Loss), Net of Tax Comprehensive income Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Comprehensive income attributable to non-controlling interest Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest Comprehensive income attributable to common stockholders Comprehensive Income (Loss), Net of Tax, Attributable to Parent Components of Deferred Tax Assets and Liabilities [Abstract] Components of Deferred Tax Assets and Liabilities [Abstract] Accrued vacation and bonuses Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Compensated Absences Accrued liabilities Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals, Accrued Liabilities Deferred compensation Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Employee Compensation Stock awards Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits, Share-based Compensation Cost Net operating loss and other carryforwards Deferred Tax Assets Operating Loss Carry Forward And Tax Credits Carry Forward Deferred tax assets operating loss carry forward and tax credits carry forward. Fixed asset basis differences Deferred Tax Assets, Property, Plant and Equipment Accumulated other comprehensive loss Deferred Tax Assets, Other Comprehensive Loss Valuation allowance Deferred Tax Assets, Valuation Allowance Total deferred tax assets Deferred Tax Assets, Gross Deferred revenue Deferred Tax Liabilities, Tax Deferred Income Fixed asset basis differences Deferred Tax Liabilities, Property, Plant and Equipment Purchased intangible assets Deferred Tax Liabilities, Intangible Assets Accumulated other comprehensive income Deferred Tax Liabilities, Other Comprehensive Income Total deferred tax liabilities Deferred Tax Liabilities, Gross Net deferred tax assets Deferred Tax Assets, Net Net deferred tax liabilities Deferred Tax Liabilities, Net Derivative Instruments Designated as Cash Flow Hedges Derivative Instruments and Hedging Activities Disclosure [Text Block] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Award Type [Axis] Award Type [Axis] Equity Award [Domain] Equity Award [Domain] Vesting stock awards Vesting Stock Awards [Member] Vesting stock awards. Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Shares of stock under stock awards Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Unvested awards, beginning balance (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Awards granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Awards assumed (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Awards Assumed Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Awards Assumed Awards forfeited (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Awards vested (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Unvested awards, ending balance (in shares) Weighted average grant date fair value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Unvested awards beginning balance (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Awards granted (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Awards assumed (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants Assumed, Weighted Average Grant Date Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants Assumed, Weighted Average Grant Date Fair Value Awards forfeited (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Awards vested (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Unvested awards ending balance (in dollars per share) Current: Current Income Tax Expense (Benefit), Continuing Operations [Abstract] Federal Current Federal Tax Expense (Benefit) State Current State and Local Tax Expense (Benefit) Deferred: Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract] Federal Deferred Federal Income Tax Expense (Benefit) State Deferred State and Local Income Tax Expense (Benefit) Total Income Tax Expense (Benefit) Schedule of Benefit Obligations in Excess of Fair Value of Plan Assets Changes in Projected Benefit Obligations, Fair Value of Plan Assets, and Funded Status of Plan [Table Text Block] Schedule of Amounts Recognized in Balance Sheet Schedule of Amounts Recognized in Balance Sheet [Table Text Block] Schedule of Assumptions Used Schedule of Assumptions Used [Table Text Block] Schedule of Allocation of Plan Assets Schedule of Allocation of Plan Assets [Table Text Block] Schedule of Expected Benefit Payments Schedule of Expected Benefit Payments [Table Text Block] Schedule of Defined Benefit Plans Disclosures [Table] Schedule of Defined Benefit Plans Disclosures [Table] Retirement Plan Type [Axis] Retirement Plan Type [Axis] Retirement Plan Type [Domain] Retirement Plan Type [Domain] Pension Plan Pension Plan [Member] RHRA Benefit Plan Retiree Health Reimbursement Account Plan [Member] Retiree Health Reimbursement Account Plan [Member] Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] 2020 Defined Benefit Plan, Expected Future Benefit Payment, Next Twelve Months 2021 Defined Benefit Plan, Expected Future Benefit Payment, Year Two 2022 Defined Benefit Plan, Expected Future Benefit Payment, Year Three 2023 Defined Benefit Plan, Expected Future Benefit Payment, Year Four 2024 Defined Benefit Plan, Expected Future Benefit Payment, Year Five Five subsequent fiscal years Defined Benefit Plan, Expected Future Benefit Payment, Five Fiscal Years Thereafter Earnings Per Share [Table] Earnings Per Share [Table] Earnings per share. Share Repurchase Program Share Repurchase Program [Axis] Share Repurchase Program Share Repurchase Program [Domain] Share Repurchase Plan Stock Repurchase Plan [Member] Stock repurchase plan. Range [Axis] Range [Axis] Range [Domain] Range [Domain] Maximum Maximum [Member] Dividends Dividends [Axis] Dividends Dividends [Domain] Quarterly Dividend Quarterly Dividend [Member] Quarterly dividend. Subsequent Event Type Subsequent Event Type [Axis] Subsequent Event Type Subsequent Event Type [Domain] Subsequent Event Subsequent Event [Member] Computation Of Earnings Per Share [Line Items] Computation Of Earnings Per Share [Line Items] Computation of earnings per share. Increase in number of shares authorized to be repurchased under the repurchase plan (in shares) Stock Repurchase Program Increase In Number Of Shares Authorized To Be Repurchased Stock repurchase program increase in number of shares authorized to be repurchased. Shares authorized to be repurchased under the repurchase plan (in shares) Stock Repurchase Program, Number of Shares Authorized to be Repurchased Shares repurchased under the repurchase plan (in shares) Stock Repurchased And Retired Under Authorization Stock repurchased and retired under authorization. Cash dividends paid per share (in dollars per share) Common Stock, Dividends, Per Share, Cash Paid Cash dividends declared per share (in dollars per share) Common Stock, Dividends, Per Share, Declared Common stock, par value (in dollars per share) Common Stock, Par or Stated Value Per Share Common stock, shares authorized (in shares) Common Stock, Shares Authorized Common stock, shares issued (in shares) Common Stock, Shares, Issued Common stock, shares outstanding (in shares) Common Stock, Shares, Outstanding Schedule of Error Corrections and Prior Period Adjustment Restatement [Table] Schedule of Error Corrections and Prior Period Adjustment Restatement [Table] Adjustments for New Accounting Pronouncements [Axis] Adjustments for New Accounting Pronouncements [Axis] Type of Adoption [Domain] Type of Adoption [Domain] Accounting Standards Update 2014-09 Accounting Standards Update 2014-09 [Member] Initial Application Period Cumulative Effect Transition [Axis] Initial Application Period Cumulative Effect Transition [Axis] Initial Application Period Cumulative Effect Transition [Domain] Initial Application Period Cumulative Effect Transition [Domain] Calculated under Revenue Guidance in Effect before Topic 606 Calculated under Revenue Guidance in Effect before Topic 606 [Member] Difference between Revenue Guidance in Effect before and after Topic 606 Difference between Revenue Guidance in Effect before and after Topic 606 [Member] Error Corrections and Prior Period Adjustments Restatement [Line Items] Error Corrections and Prior Period Adjustments Restatement [Line Items] Revenues Revenue from Contract with Customer, Excluding Assessed Tax Assets Receivables, net Liabilities and Equity Income Statement Income Statement [Abstract] Revenues Revenues Cost of revenues Cost of Revenue Operating income Operating Income (Loss) Disaggregation of Revenue Disaggregation of Revenue [Table Text Block] Contract with Customer, Asset and Liability Contract with Customer, Asset and Liability [Table Text Block] Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Table Text Block] Statutory federal income tax rate (percent) Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent Amount computed at the blended statutory federal income tax rate Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount State income taxes, net of federal tax benefit Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount Research and development and other federal credits Effective Income Tax Rate Reconciliation, Tax Credit, Research, Amount Federal income tax reduction per the Tax Act Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount Manufacturer's deduction Effective Income Tax Rate Reconciliation, Deduction, Amount Non-deductible compensation Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-based Compensation Cost, Amount Non-deductible acquisition costs Effective Income Tax Rate Reconciliation, Nondeductible Expense, Amount Excess tax benefits for stock-based compensation Effective Income Tax Rate Reconciliation, Share-based Compensation, Excess Tax Benefit, Amount Other Effective Income Tax Rate Reconciliation, Other Adjustments, Amount Effective income tax rate (percent) Effective Income Tax Rate Reconciliation, Percent Plan Name Plan Name [Axis] Plan Name Plan Name [Domain] 2013 Equity Incentive Plan Two Thousand And Thirteen Equity Incentive Plan [Member] Two thousand and thirteen equity incentive plan. Employee Stock Purchase Plan Employee Stock Purchase Plan [Member] Employee stock purchase plan. Title of Individual Title of Individual [Axis] Relationship to Entity Relationship to Entity [Domain] Directors Director [Member] Vesting Stock Awards And Employee Stock Option Granted Prior To Fiscal Twenty Fifteen Vesting Stock Awards And Employee Stock Option Granted Prior To Fiscal Twenty Fifteen [Member] Vesting stock awards and employee stock option granted prior to fiscal twenty fifteen. Employee Stock Option Granted Thereafter Employee Stock Option Granted Thereafter [Member] Employee stock option granted thereafter. Vesting Stock Awards Granted Thereafter Vesting Stock Awards Granted Thereafter [Member] Vesting stock awards granted thereafter. Employee Stock Option Employee Stock Option [Member] Performance share awards Performance Shares [Member] Vesting stock awards Share-based Payment Arrangement Share-based Payment Arrangement [Member] Share-based Payment Arrangement [Member] Share-based Payment Arrangement, Pre-combination Share-based Payment Arrangement, Pre-combination [Member] Share-based Payment Arrangement, Pre-combination [Member] Share-based Payment Arrangement, Post-combination Share-based Payment Arrangement, Post-combination [Member] Share-based Payment Arrangement, Post-combination [Member] Business combination, equity right conversion, common shares conversion ratio Business Combination, Equity Right Conversion, Common Shares Conversion Ratio Business Combination, Equity Right Conversion, Common Shares Conversion Ratio Stock granted, value, share-based compensation Stock Granted, Value, Share-based Compensation, Net of Forfeitures Accelerated compensation cost Share-based Compensation Arrangement by Share-based Payment Award Accelerated Compensation Cost Business combination, consideration transferred, equity interests issued and issuable Business Combination, Consideration Transferred, Equity Interests Issued and Issuable Number of stock based compensation plans Number Of Stock-Based Compensation Plans Number Of Stock-Based Compensation Plans Vesting period Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Percentage of stock awards vest or exercisable after one year Percentage Of Stock Awards Vest Or Exercisable After One Year Percentage of stock awards vest or exercisable after one year. Percentage of stock awards vest or exercisable after two years Percentage Of Stock Awards Vest Or Exercisable After Two Years Percentage of stock awards vest or exercisable after two years. Percentage of stock awards vest or exercisable after three years Percentage Of Stock Awards Vest Or Exercisable After Three Years Percentage of stock awards vest or exercisable after three years. Percentage of stock awards vest or exercisable after four years Percentage Of Stock Awards Vest Or Exercisable After Four Years Percentage of stock awards vest or exercisable after four years. Contractual term Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period Shares authorized under plan (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized Percentage of target shares Maximum Range Of Awards Of Target Number Of Shares The maximum percentage of target number of shares to be issued. Percentage of market price for employee purchase program for stock purchases during non-compensatory period Share-based Compensation Arrangement by Share-based Payment Award, Discount from Market Price, Purchase Date Unrecognized compensation cost, net of estimated forfeitures Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized Expected weighted-average period of recognition, years Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition Fair value of vesting awards that vested Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value Below threshold level of performance (in shares) Share Based Compensation Arrangement By Share Based Payment Award Other Than Options Lower Than Minimum Performance The minimum percentage of target number of shares to be issued. Percentage of awards presented for target number of shares Percentage Of Awards Presented For Target Number Of Shares Percentage of awards presented for target number of shares. Share awards granted upon future achievement (in shares) Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Contingently Issuable Shares Share-based compensation arrangement by share-based payment award, equity instruments other than options, contingently issuable shares. Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] Unrecognized tax benefits at beginning of the year Unrecognized Tax Benefits Additions for acquired unrecognized tax benefits Unrecognized Tax Benefits, Increase Resulting from Acquisition Additions for tax positions related to prior years Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions Additions for tax positions related to the current year Unrecognized Tax Benefits, Increase Resulting from Current Period Tax Positions Unrecognized tax benefits at end of the year Unrecognized tax benefits that, if recognized, would affect the effective income tax rate Unrecognized Tax Benefits that Would Impact Effective Tax Rate Leases [Abstract] Future Minimum Operating Lease Commitments Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block] Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Customer [Axis] Customer [Axis] Customer [Domain] Customer [Domain] Department of Defense Department Of Defense [Member] Department Of Defense [Member] Other federal government agencies Other Federal Government Agencies [Member] Other Federal Government Agencies [Member] Commercial, state and local Commercial, State, And Local Agencies [Member] Commercial, State, And Local [Member] Contract with Customer, Basis of Pricing [Axis] Contract with Customer, Basis of Pricing [Axis] Contract with Customer, Basis of Pricing [Domain] Contract with Customer, Basis of Pricing [Domain] Cost reimbursement Cost Reimbursement Contract [Member] Cost Reimbursement Contract [Member] Time and materials (T&M) Time-and-materials Contract [Member] Firm-fixed price (FFP) Fixed-price Contract [Member] Contractor [Axis] Contractor [Axis] Contractor [Axis] Contractor [Domain] Contractor [Domain] [Domain] for Contractor [Axis] Prime contractor to federal government Prime Contractor [Member] Prime Contractor [Member] Subcontractor to federal government Subcontractor [Member] Subcontractor [Member] Other Other Contractor [Member] Other Contractor [Member] Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Revenues Revenue from Contract with Customer [Text Block] Goodwill and Intangible Assets Goodwill and Intangible Assets Disclosure [Text Block] Statement of Stockholders' Equity [Abstract] Statement [Table] Statement [Table] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Shares of common stock Common Stock [Member] Additional paid-in capital Additional Paid-in Capital [Member] Retained earnings Retained Earnings [Member] Accumulated other comprehensive income (loss) AOCI Attributable to Parent [Member] Non-Controlling Interest Noncontrolling Interest [Member] Statement [Line Items] Statement [Line Items] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Balance, (in shares) Balance, beginning of period Cumulative impact from adopting ASC 606 (Note 1) on February 3, 2018 Cumulative Effect of New Accounting Principle in Period of Adoption Issuances of stock, (in shares) Stock Issued During Period, Shares, New Issues Issuances of stock Stock Issued During Period, Value, New Issues Reclassification of AOCI due to the Tax Act Tax Cuts And Jobs Act, Reclassification From AOCI To Retained Earnings, Tax Effect Tax Cuts And Jobs Act, Reclassification From AOCI To Retained Earnings, Tax Effect Other comprehensive income, net of tax Cash dividends Dividends, Common Stock, Cash Stock-based compensation Adjustments to Additional Paid in Capital, Share-based Compensation, Requisite Service Period Recognition Income tax benefits from stock-based compensation Adjustment to Additional Paid in Capital, Income Tax Effect from Share-based Compensation, Net Repurchases of stock, (in shares) Stock Repurchased and Retired During Period, Shares Repurchases of stock Stock Repurchased and Retired During Period, Value Stock issued for the Engility acquisition (in shares) Stock Issued During Period, Shares, Acquisitions Stock issued for the Engility acquisition Stock Issued During Period, Value, Acquisitions Acquired non-controlling interest Noncontrolling Interest, Increase from Business Combination Contribution from non-controlling interest Non-Controlling Interest Contribution Non-Controlling Interest Contribution Balance, (in shares) Balance, end of period Change in benefit obligation: Defined Benefit Plan, Change in Benefit Obligation [Roll Forward] Benefit obligation at acquisition Defined Benefit Plan, Benefit Obligation Benefit obligation at end of year Change in plan assets: Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] Fair value of plan assets at acquisition Defined Benefit Plan, Plan Assets, Amount Employer contributions Defined Benefit Plan, Plan Assets, Contributions by Employer Fair value of plan assets at end of year Unfunded status Defined Benefit Plan, Funded (Unfunded) Status of Plan Segment Reporting Segment Reporting, Policy [Policy Text Block] Principles of Consolidation and Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Use of Estimates Use of Estimates, Policy [Policy Text Block] Restructuring Costs Associated with Exit or Disposal Activities or Restructurings, Policy [Policy Text Block] Reporting Periods Fiscal Period, Policy [Policy Text Block] Stock-based Compensation Compensation Related Costs, Policy [Policy Text Block] Income Taxes Income Tax, Policy [Policy Text Block] Costs Allocated to Contracts Cost of Sales, Policy [Policy Text Block] Cash, Cash Equivalents and Restricted Cash Cash and Cash Equivalents, Restricted Cash and Cash Equivalents, Policy [Policy Text Block] Receivables Receivables, Policy [Policy Text Block] Inventory Inventory, Policy [Policy Text Block] Business Combinations Business Combinations Policy [Policy Text Block] Goodwill and Intangible Assets Goodwill and Intangible Assets, Policy [Policy Text Block] Impairment of Long-lived Assets Impairment or Disposal of Long-Lived Assets, Policy [Policy Text Block] Commitments and Contingencies Commitments and Contingencies, Policy [Policy Text Block] Pension and Defined Benefit Plans Pension and Other Postretirement Plans, Policy [Policy Text Block] Fair Value Measurements Fair Value Measurement, Policy [Policy Text Block] Derivative Instruments Designated as Cash Flow Hedges Derivatives, Policy [Policy Text Block] Operating Cycle Construction Contractors, Operating Cycle, Policy [Policy Text Block] Research and Development Research and Development Expense, Policy [Policy Text Block] Accounting Standards Updates New Accounting Pronouncements, Policy [Policy Text Block] Revenue Recognition Revenue from Contract with Customer [Policy Text Block] Changes in Estimates on Contracts Government Contractors, Contracts in Progress, Policy [Policy Text Block] Earnings Per Share (EPS) Earnings Per Share, Policy [Policy Text Block] Property, Plant and Equipment Property, Plant and Equipment, Policy [Policy Text Block] Debt Disclosure [Abstract] Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Debt Instrument, Redemption, Period [Axis] Debt Instrument, Redemption, Period [Axis] Debt Instrument, Redemption, Period [Domain] Debt Instrument, Redemption, Period [Domain] Debt Instrument, Redemption, Period One Debt Instrument, Redemption, Period One [Member] Debt Instrument, Redemption, Period Two Debt Instrument, Redemption, Period Two [Member] Debt Instrument, Redemption, Period Three Debt Instrument, Redemption, Period Three [Member] Debt Covenant Period [Axis] Debt Covenant Period [Axis] Debt Covenant Period [Axis] Debt Covenant Period [Domain] Debt Covenant Period [Domain] [Domain] for Debt Covenant Period Until July 31, 2016 First Term [Member] First term. After July 31, 2016 Second Term [Member] Second term. Third Term Third Term [Member] Third term. Fourth Term Fourth Term [Member] Fourth Term [Member] Credit Facility Credit Facility [Axis] Credit Facility Credit Facility [Domain] Secured Debt Secured Debt [Member] Third Amended Credit Agreement Third Amended Credit Agreement [Member] Third Amended Credit Agreement [Member] Second Amended and Restated Credit Agreement, as Amended on August 23, 2016 Second Amended And Restated Credit Agreement [Member] Second amended and restated credit agreement. Revolving Credit Facility Revolving Credit Facility [Member] February 2019 Credit Facility February 2019 Credit Facility [Member] February 2019 Credit Facility [Member] Term Loan A Facility due October 2023 February 2019 Credit Facility, Term Loan A [Member] February 2019 Credit Facility, Term Loan [Member] Term Loan B Facility due October 2025 February 2019 Credit Facility, Term Loan B [Member] February 2019 Credit Facility, Term Loan B [Member] Credit Facility due August 2021 Credit Facility due August 2021 [Member] Credit Facility due August 2021 [Member] Term Loan A Facility due August 2021 Term Loan A Facility Due August Two Thousand Twenty One [Member] Term loan A facility due august two thousand twenty one. Term Loan B Facility due May 2022 Term Loan B Facility Due May Two Thousand Twenty Two [Member] Term loan b facility due may two thousand twenty two. Term Loan B Facility Due October Two Thousand Twenty Five Term Loan B Facility Due October Two Thousand Twenty Five [Member] Term Loan B Facility Due October Two Thousand Twenty Five [Member] Term Loan A Facility Commitment Due October Two Thousand Twenty Three Term Loan A Facility Commitment Due October Two Thousand Twenty Three [Member] Term Loan A Facility Commitment Due October Two Thousand Twenty Three Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type Long-term Debt, Type [Domain] Line of Credit Line of Credit [Member] Minimum Minimum [Member] Variable Rate Variable Rate [Axis] Variable Rate Variable Rate [Domain] Eurocurrency Rate Eurodollar [Member] Base Rate Base Rate [Member] London Interbank Offered Rate (LIBOR) London Interbank Offered Rate (LIBOR) [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Credit facility, maximum borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity Debt instrument, face amount Debt Instrument, Face Amount Debt instrument, reduction to interest rate margin Debt Instrument, Reduction To Interest Rate Margin Debt Instrument, Reduction To Interest Rate Margin Interest rate margin under credit agreement Debt Instrument, Basis Spread on Variable Rate Debt instrument floor rate Debt Instrument Floor Rate Debt instrument floor rate. Deferred financing fees Principal amount of long-term debt Long-term Debt, Gross Long term debt, gross, merger termination feature Long Term Debt, Gross, Merger Termination Feature Long Term Debt, Gross, Merger Termination Feature Interest expense Interest Expense Payments of financing fees Payments of Financing Costs Amortization rate Debt Instrument, Amortization Rate Debt Instrument, Amortization Rate Principal payments on borrowings Repayments of Long-term Debt Commitment fee percentage Line of Credit Facility, Commitment Fee Percentage Credit agreement financial covenant, leverage ratio Ratio Of Indebtedness To Earnings Before Interest Taxes Depreciation And Amortization Ratio of indebtedness to earnings before interest taxes depreciation and amortization. Schedule of Finite-Lived Intangible Assets Schedule of Finite-Lived Intangible Assets [Table Text Block] Schedule of Estimated Annual Amortization Expense Related To Intangible Assets Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] Capitalized Contract Cost [Axis] Capitalized Contract Cost [Axis] Capitalized Contract Cost [Domain] Capitalized Contract Cost [Domain] Pre-contract costs Pre-Contract Cost [Member] Pre-Contract Cost [Member] Pre-contract cost, not awarded Pre-Contract Cost, Not Awarded [Member] Pre-Contract Cost, Not Awarded [Member] Fulfillment costs - current Fulfillment Cost, Current [Member] Fulfillment Cost, Current [Member] Contract with customer, performance obligation satisfied in previous period Contract with Customer, Performance Obligation Satisfied in Previous Period Contract with customer, liability, revenue recognized Contract with Customer, Liability, Revenue Recognized Capitalized contract cost, amortization Capitalized Contract Cost, Amortization Revenue, remaining performance obligation, amount Revenue, Remaining Performance Obligation, Amount Reconciliation of Weighted Average Number of Shares Outstanding Used to Compute Basic and Diluted EPS Schedule of Weighted Average Number of Shares [Table Text Block] Stock-Based Awards Excluded from Weighted Average Number of Shares Outstanding Used to Compute Diluted EPS Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Restricted Stock Restricted Stock [Member] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Common Stock Cash consideration paid to extinguish Engility outstanding debt Payments to Acquire Businesses, Gross Purchase price Business Combination, Consideration Transferred New shares (in shares) Business Acquisition, Equity Interest Issued or Issuable, Number of Shares Share price (in dollars per share) Business Acquisition, Share Price Favorable adjustments Increase In Income From Change In Contract Estimates Increase in income from change in contract estimates. Unfavorable adjustments Decrease In Income From Change In Contract Estimates Decrease in income from change in contract estimates. Net (unfavorable) favorable adjustments Increase Decrease In Income From Change In Contract Estimates Increase (decrease) in income from change in contract estimates. Income tax effect Change In Contract Estimates Income Tax Effect Change in contract estimates income tax effect. Net (unfavorable) favorable adjustments, after tax Increase Decrease In Income From Change In Contract Estimates Net Of Tax Increase (decrease) in income from change in contract estimates net of tax. Basic EPS impact (in dollars per share) Increase Decrease In Income From Change In Contract Estimates Per Basic Share Increase (decrease) in income from change in contract estimates per basic share. Diluted EPS impact (in dollars per share) Increase Decrease In Income From Change In Contract Estimates Per Diluted Share Increase (decrease) in income from change in contract estimates per diluted share. Restricted cash included in other assets Restricted Cash and Cash Equivalents, Noncurrent Cash, cash equivalents and restricted cash Defined Benefit Plan, Plan Assets, Category [Axis] Defined Benefit Plan, Plan Assets, Category [Axis] Defined Benefit Plan, Plan Assets, Category [Domain] Defined Benefit Plan, Plan Assets, Category [Domain] Defined Benefit Plan, Equity Securities, US Defined Benefit Plan, Equity Securities, US [Member] Defined Benefit Plan, Equity Securities, Non-US Defined Benefit Plan, Equity Securities, Non-US [Member] Fixed Income Securities Fixed Income Securities [Member] Defined Benefit Plan, Cash and Cash Equivalents Defined Benefit Plan, Cash and Cash Equivalents [Member] Company contributions to defined contribution plans expense Defined Contribution Plan, Cost Defined benefit plan liability Liability, Defined Benefit Plan Benefit obligation Plan assets, amount Long-term rate of return Defined Benefit Plan, Plan Assets, Long-term Rate of Return Defined Benefit Plan, Plan Assets, Long-term Rate of Return Target allocation, percentage Defined Benefit Plan, Plan Assets, Target Allocation, Percentage Unrealized (loss) gain on derivative instruments, tax benefit (expense) Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, Tax Reclassification adjustment for (benefits) costs realized in net income, tax expense (benefit) Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, Tax Basic EPS (in dollars per share) Earnings Per Share, Basic Diluted EPS (in dollars per share) Earnings Per Share, Diluted Schedule of Property, Plant and Equipment Property, Plant and Equipment [Table Text Block] Revenues Business Acquisition, Pro Forma Revenue Net income attributable to common stockholders Business Acquisition, Pro Forma Net Income (Loss) Stock options Basic weighted-average number of shares outstanding (in shares) Weighted Average Number of Shares Outstanding, Basic Dilutive common share equivalents - stock options and other stock-based awards (in shares) Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Diluted weighted-average number of shares outstanding (in shares) Weighted Average Number of Shares Outstanding, Diluted Antidilutive stock options excluded (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Long Term Debt Schedule of Long-term Debt Instruments [Table Text Block] Maturities of Long-term Debt Schedule of Maturities of Long-term Debt [Table Text Block] Engility Acquisition Business Combination Disclosure [Text Block] Selling, general and administrative expenses Selling, General and Administrative Expense Acquisition and integration costs (Note 4) Business Combination Acquisition And Integration Related Costs This element represents acquisition-related and integration related costs incurred to effect a business combination which costs have been expensed during the period. Such costs include finder's fees; advisory, legal, accounting, valuation, other professional or consulting fees; general administrative costs, including the costs of maintaining an internal acquisitions department; including costs of registering and issuing debt and equity securities; business integration costs, systems integration and conversion costs, and severance and other employee-related costs. Operating income Interest expense Other (income) expense, net Other Nonoperating Income (Expense) Income before income taxes Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Provision for income taxes (Note 9) Net income Net income attributable to non-controlling interest Net Income (Loss) Attributable to Noncontrolling Interest Net income attributable to common stockholders Earnings per share (Note 2): Earnings Per Share, Basic and Diluted [Abstract] Basic (in dollars per share) Diluted (in dollars per share) Nonrecurring Adjustment [Axis] Nonrecurring Adjustment [Axis] Nonrecurring Adjustment [Domain] Nonrecurring Adjustment [Domain] Acquisition-related Costs Acquisition-related Costs [Member] Debt instrument, term Debt Instrument, Term Business acquisition, transaction costs Business Acquisition, Transaction Costs Acquisition related costs Business Combination, Acquisition Related Costs Payments of debt issuance costs Payments of stock issuance costs Integration related costs Business Combination, Integration Related Costs Revenues Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual Loss from acquisition Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual Rental expense for facilities and equipment Operating Leases, Rent Expense Other accrued liabilities Liability, Defined Benefit Plan, Current Other long-term liabilities Liability, Defined Benefit Plan, Noncurrent Net amount recognized 2020 Operating Leases, Future Minimum Payments Due, Next Twelve Months 2021 Operating Leases, Future Minimum Payments, Due in Two Years 2022 Operating Leases, Future Minimum Payments, Due in Three Years 2023 Operating Leases, Future Minimum Payments, Due in Four Years 2024 Operating Leases, Future Minimum Payments, Due in Five Years Thereafter Operating Leases, Future Minimum Payments, Due Thereafter Total Operating Leases, Future Minimum Payments Due Property, Plant and Equipment [Table] Property, Plant and Equipment [Table] Property, Plant and Equipment, Type Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type Property, Plant and Equipment, Type [Domain] Computer equipment Computer Equipment [Member] Capitalized software and software licenses Software and Software Development Costs [Member] Leasehold improvements Leasehold Improvements [Member] Office furniture and fixtures Furniture and Fixtures [Member] Buildings and improvements Building and Building Improvements [Member] Construction in process Construction in Progress [Member] Land Land [Member] Property, Plant and Equipment [Line Items] Property, Plant and Equipment [Line Items] Depreciation or amortization method Property, Plant and Equipment, Depreciation Methods Estimated useful lives (in years) Property, Plant and Equipment, Estimated Useful Lives Estimated useful lives (in years) Property, Plant and Equipment, Useful Life Property, plant, and equipment Property, Plant and Equipment, Gross Accumulated depreciation and amortization Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Property, plant, and equipment, net Ineffective portion of the unrealized change in fair value, net of tax Derivative, Net Hedge Ineffectiveness Gain (Loss) Unrealized gains from accumulated other comprehensive loss Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net Shares of stock under performance shares Performance shares granted (in shares) Performance shares forfeited (in shares) Performance shares vested (in shares) Performance shares adjustment (in shares) Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Adjustment Share based compensation arrangement by share based payment award equity instruments other than options adjustment. Performance shares granted (in dollars per share) Performance shares forfeited (in dollars per share) Performance shares vested (in dollars per share) Performance shares adjustment (in dollars per share) Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Adjustment In Period Weighted Average Grant Date Fair Value Share based compensation arrangement by share based payment award equity instruments other than options adjustment in period weighted average grant date fair value. Selected Quarterly Financial Data (Unaudited) Quarterly Financial Information [Table Text Block] Business Segment Information Segment Reporting Disclosure [Text Block] Schedule of Business Acquisitions, by Acquisition Schedule of Business Acquisitions, by Acquisition [Table Text Block] Schedule of Recognized Identified Assets Acquired and Liabilities Assumed Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block] Schedule of Indefinite-lived Intangible Assets Acquired as Part of Business Combination Schedule of Finite-Lived Intangible Assets Acquired as Part of Business Combination [Table Text Block] Schedule of Unaudited Pro Forma Financial Information Business Acquisition, Pro Forma Information [Table Text Block] Weighted average grant-date fair value Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value Expected term (in years) Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term Expected volatility Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Volatility Rate Risk-free interest rate Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Risk Free Interest Rate Dividend yield Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Dividend Rate Finite-Lived Intangible Assets by Major Class Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name Finite-Lived Intangible Assets, Major Class Name [Domain] Backlog Order or Production Backlog [Member] Developed technology Technology-Based Intangible Assets [Member] Customer relationships Customer Relationships [Member] Amount Finite-lived Intangible Assets Acquired Weighted-Average Amortization Period Acquired Finite-lived Intangible Assets, Weighted Average Useful Life Stated interest rate Debt Instrument, Interest Rate, Stated Percentage Effective interest rate Debt Instrument, Interest Rate, Effective Percentage Total principal payments Principal amount of long-term debt, current Debt Instrument Current Carrying Amount Debt instrument current carrying amount. Principal amount of long-term debt, non current Debt Instrument Non Current Carrying Amount Debt instrument non current carrying amount. Unamortized Debt Issuance Costs Debt Issuance Costs, Net Unamortized debt issuance costs, current Debt Issuance Costs, Current, Net Unamortized debt issuance costs, non current Debt Issuance Costs, Noncurrent, Net Total long-term debt Long-term Debt Less current portion Total long-term debt, net of current portion Income Taxes [Table] Income Taxes [Table] Income taxes. Nature of Uncertainty [Axis] Nature of Uncertainty [Axis] Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Nature of Uncertainty [Domain] Significant Change in Unrecognized Tax Benefits is Reasonably Possible, Nature of Uncertainty [Domain] Settlement with Taxing Authority Settlement with Taxing Authority [Member] Statute of Limitations Expiration Statute of Limitations Expiration [Member] Statute of Limitations Expiration [Member] Income Tax Authority Income Tax Authority [Axis] Income Tax Authority Income Tax Authority [Domain] State State and Local Jurisdiction [Member] Scitor Holdings, Inc. Scitor Holdings Inc [Member] Scitor Holdings Inc. Income Taxes [Line Items] Income Taxes [Line Items] Income taxes. Excess tax benefits from share-based award payments Net deferred tax assets Reversal unrecognized tax benefits reasonably possible Decrease in Unrecognized Tax Benefits is Reasonably Possible Tax deductible goodwill Tax deductible identified intangible assets Business Acquisition Purchase Price Allocation Identified Intangible Assets Expected Tax Deductible Amount Business acquisition purchase price allocation identified intangible assets expected tax deductible amount. Federal and state net operating loss Deferred Tax Assets, Operating Loss Carryforwards Carryforward amount, eliminated Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Tax Credit Carryforward Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Tax Credit Carryforward Operating loss carryforwards Operating Loss Carryforwards Carryforward amount Tax Credit Carryforward, Amount Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Unrealized Gains (losses) on Fixed Interest Rate Swap Cash Flow Hedges Accumulated Gain (Loss), Cash Flow Hedge, Including Noncontrolling Interest [Member] Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] Balance, beginning of period AOCI Including Portion Attributable to Noncontrolling Interest, before Tax Other comprehensive income before reclassifications Other Comprehensive Income (Loss), before Reclassifications, before Tax Amounts reclassified from accumulated other comprehensive loss Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax Net other comprehensive income Other Comprehensive Income (Loss), before Tax Balance, end of period Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table] Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table] Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] Total stock-based compensation expense Tax benefits recognized from stock-based compensation Employee Service Share-based Compensation, Tax Benefit from Compensation Expense Benefit obligation, discount rate Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate 2020 Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months 2021 Long-term Debt, Maturities, Repayments of Principal in Year Two 2022 Long-term Debt, Maturities, Repayments of Principal in Year Three 2023 Long-term Debt, Maturities, Repayments of Principal in Year Four 2024 Long-term Debt, Maturities, Repayments of Principal in Year Five Thereafter Long-term Debt, Maturities, Repayments of Principal after Year Five Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Receivables, net Trade Accounts Receivable [Member] Other assets Other Assets [Member] Other accrued liabilities Other Accrued LIabilities [Member] Other Accrued LIabilities [Member] Other long-term liabilities Other Noncurrent Liabilities [Member] Billed and billable receivables, net Billed Contracts Receivable Contract assets Contract with Customer, Asset, Net Contract liabilities Contract with Customer, Liability, Noncurrent Allowance for doubtful accounts receivable Allowance for Doubtful Accounts Receivable Mutual funds Mutual Fund [Member] Guaranteed deposit account Guaranteed Deposit Account [Member] Guaranteed Deposit Account [Member] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Quoted Prices in Active Markets for Identical Assets (Level 1) Fair Value, Inputs, Level 1 [Member] Significant Other Observable Inputs (Level 2) Fair Value, Inputs, Level 2 [Member] Significant Unobservable Inputs (Level 3) Fair Value, Inputs, Level 3 [Member] Debt Obligations Debt Disclosure [Text Block] Schedule of Finite-Lived Intangible Assets [Table] Schedule of Finite-Lived Intangible Assets [Table] Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Gross carrying value Finite-Lived Intangible Assets, Gross Accumulated amortization Finite-Lived Intangible Assets, Accumulated Amortization Net carrying value Document And Entity Information [Abstract] Document and entity information. Document Type Document Type Amendment Flag Amendment Flag Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Trading Symbol Trading Symbol Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Well-known Seasoned Issuer Entity Well-known Seasoned Issuer Entity Current Reporting Status Entity Current Reporting Status Entity Voluntary Filers Entity Voluntary Filers Entity Filer Category Entity Filer Category Entity Emerging Growth Company Entity Emerging Growth Company Entity Shell Company Entity Shell Company Entity Small Business Entity Small Business Entity Common Stock, Shares Outstanding (in shares) Entity Common Stock, Shares Outstanding Entity Public Float Entity Public Float Operating Leases Lessee, Operating Lease, Disclosure [Table Text Block] Significant Accounting Policies [Table] Significant Accounting Policies [Table] Significant accounting policies. Ownership [Axis] Ownership [Axis] Ownership [Domain] Ownership [Domain] Forfeiture Support Associates J.V. Forfeiture Support Associates J.V. [Member] Forfeiture Support Associates J.V. [Member] Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Cost of Sales Cost of Sales [Member] Selling, General and Administrative Expenses Selling, General and Administrative Expenses [Member] New Accounting Pronouncement, Early Adoption [Axis] New Accounting Pronouncement, Early Adoption [Axis] New Accounting Principles, Early Adoption [Domain] New Accounting Principles, Early Adoption [Domain] New Accounting Pronouncement, Early Adoption, Effect New Accounting Pronouncement, Early Adoption, Effect [Member] Retained Earnings AOCI Attributable to Parent Restructuring Type [Axis] Restructuring Type [Axis] Type of Restructuring [Domain] Type of Restructuring [Domain] Employee Severance Employee Severance [Member] Contract Termination Contract Termination [Member] Accounting Standards Update 2014-09, Revenue Recognition, Adjusted Cost-To-Cost Basis Accounting Standards Update 2014-09, Revenue Recognition, Adjusted Cost-To-Cost Basis [Member] Accounting Standards Update 2014-09, Revenue Recognition, Adjusted Cost-To-Cost Basis [Member] Accounting Standards Update 2016-09 Accounting Standards Update 2016-09 [Member] Accounting Standards Update 2016-18 Accounting Standards Update 2016-18 [Member] Accounting Standards Update 2018-02 Accounting Standards Update 2018-02 [Member] Accounting Standards Update 2018-02 [Member] Significant Accounting Policies [Line Items] Significant Accounting Policies [Line Items] Significant accounting policies. Definitive agreement to acquire business, percentage of acquisition Business Acquisition, Percentage of Voting Interests Acquired Ownership percentage Noncontrolling Interest, Ownership Percentage by Parent Total restructuring costs Restructuring and Related Cost, Cost Incurred to Date Cash payments for restructuring costs Payments for Restructuring Income tax expense (benefit) Tax Cuts and Jobs Act of 2017, Income Tax Expense (Benefit) Tax Cuts and Jobs Act of 2017, Income Tax Expense (Benefit) Net benefit recorded related to the re-measurement of net deferred tax liabilities Tax Cuts And Jobs Act of 2017, Incomplete Accounting, Change In Tax Rate, Provisional Income Tax Expense (Benefit) Tax Cuts And Jobs Act of 2017, Incomplete Accounting, Change In Tax Rate, Provisional Income Tax Expense (Benefit) Additional benefit recorded related to the re-measurement of net deferred tax liabilities Tax Cuts and Jobs Act, Measurement Period Adjustment, Income Tax Expense (Benefit) Tax Cuts and Jobs Act, Measurement Period Adjustment, Income Tax Expense (Benefit) Outstanding payments Oustanding Checks Oustanding Checks Unbilled receivables, maximum expected period for billing and collection Expected Period For Revenues To Be Billed And Collected On Uncompleted Contracts Maximum expected period for billing and collection of unbilled receivables. Amount of progress payments received are offset against unbilled receivables Construction Contract Cost, Progress Payment Offset Unbilled receivables Unbilled Receivables, Current Provisions for inventory and deferred contract costs Inventory, Firm Purchase Commitment, Loss Impairment of goodwill and intangible assets Goodwill and Intangible Asset Impairment Operating cycle (in years) Operating Cycle Internal research and development costs included in selling, general and administrative expenses Research and Development Expense Inventory, prepaid expenses, and other current assets Inventory, Prepaid Expenses, And Other Current Assets Inventory, Prepaid Expenses, And Other Current Assets Other current assets (Increase) decrease in net cash used in investing activities Net Cash Provided by (Used in) Investing Activities, Continuing Operations Capitalized Contract Cost [Table] Capitalized Contract Cost [Table] Other current assets Other Current Assets [Member] Fulfillment costs - non-current Fulfillment Cost, Non-Current [Member] Fulfillment Cost, Non-Current [Member] Capitalized Contract Cost [Line Items] Capitalized Contract Cost [Line Items] Capitalized contract cost, net Capitalized Contract Cost, Net Commitments and Contingencies Disclosure [Abstract] Commitments And Contingencies [Table] Commitments And Contingencies [Table] Commitments and contingencies. Legal Entity Legal Entity [Axis] Entity Entity [Domain] Former Parent Former Parent [Member] Former parent. Loss Contingency Nature Loss Contingency Nature [Axis] Loss Contingency, Nature Loss Contingency, Nature [Domain] Government Investigations and Reviews Government Investigations And Reviews [Member] Government investigations and reviews. Letters of Credit Financial Standby Letter of Credit [Member] Surety Bonds Surety Bond [Member] Commitments And Contingencies [Line Items] Commitments And Contingencies [Line Items] Commitments and contingencies. Payments to acquire businesses, net of cash acquired Business combination amount deposited to adjustment and indemnification escrow accounts included in cash consideration paid Business Combination Amount Deposited To Adjustment And Indemnification Escrow Accounts Included In Cash Consideration Paid Business combination amount deposited to adjustment and indemnification escrow accounts included in cash consideration paid. Business combination amount deposited to adjustment and indemnification escrow accounts amounts released Business Combination Amount Deposited To Adjustment And Indemnification Escrow Accounts Amounts Released Business combination amount deposited to adjustment and indemnification escrow accounts amounts released. Business combination, escrow deposit disbursements received Business Combination, Escrow Deposit Disbursements Received Business Combination, Escrow Deposit Disbursements Received Escrow deposit Escrow Deposit Contingent losses, threshold for loss sharing with former parent Loss Contingency Threshold For Loss Sharing Loss contingency threshold for loss sharing with former Parent. Contingent losses, loss sharing percentage in excess of threshold Loss Contingency Loss Sharing Percentage In Excess Of Threshold Loss contingency loss sharing percentage in excess of threshold. Estimated net amounts to be refunded for potential adjustments Loss Contingency Accrual Outstanding obligations Guarantor Obligations, Current Carrying Value 2020 Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months 2021 Finite-Lived Intangible Assets, Amortization Expense, Year Two 2022 Finite-Lived Intangible Assets, Amortization Expense, Year Three 2023 Finite-Lived Intangible Assets, Amortization Expense, Year Four 2024 Finite-Lived Intangible Assets, Amortization Expense, Year Five Thereafter Finite-Lived Intangible Assets, Amortization Expense, after Year Five Schedule Of Fiscal Period Schedule Of Fiscal Period [Table Text Block] Schedule Of Fiscal Period Schedule of Restricted Cash Restrictions on Cash and Cash Equivalents [Table Text Block] Schedule of Cash and Cash Equivalents Schedule of Cash and Cash Equivalents [Table Text Block] Schedule of New Accounting Pronouncements and Changes in Accounting Principles Schedule of New Accounting Pronouncements and Changes in Accounting Principles [Table Text Block] Legal Proceedings and Commitments and Contingencies Legal Matters and Contingencies [Text Block]