Equity [Abstract] Schedule of Stock by Class [Table] Schedule of Stock by Class [Table] Class of Stock [Axis] Class of Stock [Axis] Class of Stock [Domain] Class of Stock [Domain] Common stock, Class A Common Class A [Member] Class of Stock [Line Items] Class of Stock [Line Items] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Common stock, shares issued, beginning of period Shares, Outstanding Issuance of common stock Stock Issued During Period, Shares, New Issues Stock options exercised Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Common stock, shares issued, end of period Treasury stock, shares, beginning of period Treasury Stock, Shares Treasury stock, shares, end of period Repurchase of common stock Treasury Stock, Shares, Acquired Repurchase of common stock, value, cost method Treasury Stock, Value, Acquired, Cost Method Organization, Consolidation and Presentation of Financial Statements [Abstract] Excess Tax Benefit from Share-based Compensation, Operating Activities Excess Tax Benefit from Share-based Compensation, Operating Activities Business Combinations [Abstract] Schedule of Consideration Transferred 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] Number of operating segments Number of Operating Segments Number of employees Entity Number of Employees Disclosure of Compensation Related Costs, Share-based Payments [Abstract] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Plan Name [Axis] Plan Name [Axis] Plan Name [Domain] Plan Name [Domain] EIP Amended and Restated Equity Incentive Plan [Member] Amended and Restated Equity Incentive Plan [Member] Annual Incentive Plan Annual Incentive Plan [Member] Annual Incentive Plan [Member] Award Type [Axis] Award Type [Axis] Award Type [Domain] Equity Award [Domain] Stock options Employee Stock Option [Member] Restricted stock Restricted Stock [Member] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Unrecognized compensation cost related to unvested stock-based compensation agreements Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized Unrecognized compensation cost, amortization period Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition Compensation and Retirement Disclosure [Abstract] Employer Matching Contribution, Percent of Match Defined Contribution Plan, Employer Matching Contribution, Percent of Match Employees’ Capital Accumulation Plan, Total expense recognized Defined Contribution Plan, Cost Recognized Employees’ Capital Accumulation Plan, Company-paid contributions Defined Contribution Plan, Employer Discretionary Contribution Amount Schedule of Defined Benefit Plans Disclosures [Table] Schedule of Defined Benefit Plans Disclosures [Table] Defined Benefit Plans and Other Postretirement Benefit Plans [Axis] Defined Benefit Plans and Other Postretirement Benefit Plans [Axis] Defined Benefit Plans and Other Postretirement Benefit Plans [Domain] Defined Benefit Plan and Other Postretirement Benefit Plan [Domain] Supplemental Employee Retirement Plan Supplemental Employee Retirement Plan [Member] Officer Medical Plan Other Pension Plan, Postretirement or Supplemental Plans [Member] Defined Benefit Plan Disclosure [Line Items] Defined Benefit Plan Disclosure [Line Items] Service cost Defined Benefit Plan, Service Cost Interest cost Defined Benefit Plan, Interest Cost Net actuarial loss Defined Benefit Plan, Amortization of Gains (Losses) Total benefit cost Defined Benefit Plan, Net Periodic Benefit Cost Defined benefit plan, unfunded status of plan Defined Benefit Plan, Funded Status of Plan Deferred Compensation Arrangement with Individual, Annual Cash Award Granted per Year of Service, Amount Deferred Compensation Arrangement with Individual, Annual Cash Award Granted per Year of Service, Amount Deferred Compensation Arrangement with Individual, Annual Cash Award Granted per Year of Service, Amount STOCKHOLDERS' EQUITY Stockholders' Equity Note Disclosure [Text Block] Compensation Related Costs [Abstract] Bonus Accrued Bonuses, Current Retirement Pension and Other Postretirement and Postemployment Benefit Plans, Liabilities, Current Vacation Accrued Vacation, Current Other Other Employee-related Liabilities, Current Total accrued compensation and benefits Employee-related Liabilities, Current Payables and Accruals [Abstract] Schedule of Accounts Payable and Accrued Liabilities [Table Text Block] Schedule of Accounts Payable and Accrued Liabilities [Table Text Block] ACCUMULATED OTHER COMPREHENSIVE LOSS Comprehensive Income (Loss) Note [Text Block] Other Liabilities Disclosure [Abstract] OTHER LONG-TERM LIABILITIES Other Liabilities Disclosure [Text Block] Stock Issued During Period, Shares, Employee Stock Purchase Plans Stock Issued During Period, Shares, Employee Stock Purchase Plans Commitments and Contingencies Disclosure [Abstract] Loss Contingencies [Table] Loss Contingencies [Table] Concentration Risk Type [Axis] Concentration Risk Type [Axis] Concentration Risk Type [Domain] Concentration Risk Type [Domain] Government Contracts Concentration Risk [Member] Government Contracts Concentration Risk [Member] Loss Contingency Nature [Axis] Loss Contingency Nature [Axis] Loss Contingency, Nature [Domain] Loss Contingency, Nature [Domain] Former stockholder litigation Former Stockholder Litigation [Member] Former Stockholder Litigation [Member] Litigation Court [Axis] Litigation Court [Axis] Litigation Court [Axis] Litigation Court Type [Domain] Litigation Court Type [Domain] Litigation Court Type [Domain] United States District Court for Southern District of New York United States District Court for Southern District of New York [Member] United States District Court for Southern District of New York [Member] Loss Contingencies [Line Items] Loss Contingencies [Line Items] Concentration risk, percentage Concentration Risk, Percentage Loss contingencies, number of plaintiffs Loss Contingency, Number of Plaintiffs Loss contingencies, new claims filed, number Loss Contingency, New Claims Filed, Number Loss contingencies, claims amended, number Loss Contingency, Claims Amended, Number Loss Contingency, Claims Amended, Number Loss contingencies, claims dismissed, number Loss Contingency, Claims Settled and Dismissed, Number Loss contingencies, claims settled, number Loss Contingency, Claims Settled, Number Loss contingencies, pending claims, number Loss Contingency, Pending Claims, Number Subsequent Events [Abstract] Subsequent Events Subsequent Events [Text Block] Receivables [Abstract] ACCOUNTS RECEIVABLE, NET Loans, Notes, Trade and Other Receivables Disclosure [Text Block] Related Party Transactions [Abstract] Schedule of Related Party Transactions, by Related Party [Table] Schedule of Related Party Transactions, by Related Party [Table] Related Party [Axis] Related Party [Axis] Related Party [Domain] Related Party [Domain] Affiliated Entity Affiliated Entity [Member] Related Party Transaction [Axis] Related Party Transaction [Axis] Related Party Transaction [Domain] Related Party Transaction [Domain] Pledge Obligation Pledge Obligation [Member] Pledge Obligation [Member] Related Party Transaction [Line Items] Related Party Transaction [Line Items] Due to Affiliate, Current Due to Affiliate, Current Fair Value Disclosures [Abstract] Recurring Fair Value Measurements Fair Value Measurements, Recurring and Nonrecurring [Table Text Block] 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] Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Cost of revenue Cost of Sales [Member] General and administrative expenses General and Administrative Expense [Member] Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items] Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items] Stock-based compensation expense Allocated Share-based Compensation Expense Debt Disclosure [Abstract] Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Secured Debt Secured Debt [Member] Revolving Credit Facility Revolving Credit Facility [Member] Senior Notes Senior Notes [Member] Debt Instrument [Axis] Debt Instrument [Axis] Debt Instrument, Name [Domain] Debt Instrument, Name [Domain] Term Loan A Tranche-A Loans [Member] Tranche A Loans [Member] Term Loan B Tranche B Loans [Member] Tranche B Loans [Member] Senior Notes due 2025 Senior Notes Due 2025 [Member] Senior Notes Due 2025 [Member] Debt Instrument [Line Items] Debt Instrument [Line Items] Interest Expense, Debt Interest Expense, Debt Deferred Payment Obligation, Accrued Interest Payment Deferred Payment Obligation, Interest Payment Deferred Payment Obligation, Interest Payment Amortization of Debt Issuance Costs (DIC) and Original Issue Discount (OID) Amortization of Debt Issuance Costs and Discounts Interest Expense, Other Interest Expense, Other Interest Expense Interest Expense Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Business Acquisitions, by Acquisition [Table] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Customer Relationships Customer Relationships [Member] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] Aquilent eGov Holdings, Inc. (d/b/a Aquilent) [Member] eGov Holdings, Inc. (d/b/a Aquilent) Business Acquisition [Line Items] Business Acquisition [Line Items] Acquisition-related contingent consideration Business Combination, Contingent Consideration, Liability Customer-relationship intangible assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill Finite-lived intangible asset, useful life (in years) Finite-Lived Intangible Asset, Useful Life Tax indemnification liability Business Combination, Tax Indemnification Liability Business Combination, Tax Indemnification Liability Income tax uncertainty Liability for Uncertainty in Income Taxes, Noncurrent Goodwill Goodwill ACCRUED COMPENSATION AND BENEFITS Compensation Related Costs, General [Text Block] STOCK-BASED COMPENSATION Disclosure of Compensation Related Costs, Share-based Payments [Text Block] DEBT Debt Disclosure [Text Block] Components of net postretirement medical expense Schedule of Net Benefit Costs [Table Text Block] Current assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets Other tangible assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets Current liabilities Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities Tax liability Income tax uncertainty Total purchase consideration transfer at closing Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net Common stock shares activity Schedule of Common Stock Outstanding Roll Forward [Table Text Block] Statement of Cash Flows [Abstract] Cash flows from operating activities Net Cash Provided by (Used in) Operating Activities [Abstract] Net income Net Income (Loss) Attributable to Parent Adjustments to reconcile net income to net cash provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation and amortization Depreciation, Depletion and Amortization Stock-based compensation expense Share-based Compensation Excess tax benefits from stock-based compensation Amortization of debt issuance costs and loss on extinguishment Amortization Of Financing Costs And Discounts and Loss on Extinguishment of Debt Amortization Of Financing Costs And Discounts and Loss on Extinguishment of Debt Losses on dispositions Gain (Loss) on Disposition of Assets Changes in assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Accounts receivable Increase (Decrease) in Accounts Receivable Prepaid expenses and other current assets Increase (Decrease) in Prepaid Expense and Other Assets Other long-term assets Increase (Decrease) in Other Noncurrent Assets Accrued compensation and benefits Increase (Decrease) in Employee Related Liabilities Accounts payable and other accrued expenses Increase (Decrease) in Accounts Payable and Accrued Liabilities Accrued interest Increase (Decrease) in Interest Payable, Net Other current liabilities Increase (Decrease) in Other Operating 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] Purchases of property and equipment Payments to Acquire Property, Plant, and Equipment Cash paid for business acquisitions, net of cash acquired Payments to Acquire Businesses, Net of Cash Acquired Insurance proceeds received for damage to equipment Proceeds from Insurance Settlement, Investing Activities 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] Proceeds from issuance of common stock Proceeds from Issuance of Common Stock Stock option exercises Proceeds from Stock Options Exercised Excess tax benefits from stock-based compensation Excess Tax Benefit from Share-based Compensation, Financing Activities Repurchases of common stock Payments for Repurchase of Common Stock Cash dividends paid Payments of Dividends Dividend equivalents paid to option holders Payments of Capital Distribution Repayment of debt Repayments of Debt Proceeds from debt issuance Proceeds from Issuance of Long-term Debt Net cash provided by (used in) financing activities Net Cash Provided by (Used in) Financing Activities Net increase in cash and cash equivalents Cash and Cash Equivalents, Period Increase (Decrease) Cash and cash equivalents-beginning of period Cash and Cash Equivalents, at Carrying Value Cash and cash equivalents-end of period Supplemental disclosures of cash flow information Supplemental Cash Flow Information [Abstract] Cash paid during the period for: Cash Payments Abstract Cash paid during the period for: Interest Interest Paid Income taxes Income Taxes Paid, Net FAIR VALUE MEASUREMENTS Fair Value Disclosures [Text Block] Concentration Risk [Table] Concentration Risk [Table] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Axis] Guarantor Obligations, Nature [Domain] Guarantor Obligations, Nature [Domain] Financial Standby Letter of Credit Financial Standby Letter of Credit [Member] Contracts with U.S. government agencies or other U.S. government contractors Concentration Risk [Line Items] Concentration Risk [Line Items] Guarantor Obligations, Current Carrying Value Guarantor Obligations, Current Carrying Value Guarantor Obligations, Liquidation Proceeds, Monetary Amount Guarantor Obligations, Liquidation Proceeds, Monetary Amount Guarantor Obligations, Facility Guarantor Obligations, Facility Guarantor Obligations, Facility Guarantor Obligations, Available Amount Guarantor Obligations, Available Amount Guarantor Obligations, Available Amount Unfavorable Regulatory Action Unfavorable Regulatory Action [Member] Liability for reductions and/or penalties from U.S Governement audits Loss Contingency Accrual Statement of Comprehensive Income [Abstract] Unrealized loss on derivatives designated as cash flow hedges Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax Change in postretirement plan costs Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Gain (Loss), Net of Tax Total other comprehensive (loss) income, net of tax Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Comprehensive income Comprehensive Income (Loss), Net of Tax, Attributable to Parent EMPLOYEE BENEFIT PLANS Pension and Other Postretirement Benefits Disclosure [Text Block] Statement of Financial Position [Abstract] Statement [Table] Statement [Table] Statement [Line Items] Statement [Line Items] Common stock, par value Common Stock, Par or Stated Value Per Share Common stock, shares authorized Common Stock, Shares Authorized Common stock, shares issued Common Stock, Shares, Issued Common stock, shares outstanding Common Stock, Shares, Outstanding Treasury stock, shares Derivative Instruments and Hedging Activities Disclosure [Abstract] Derivatives Derivative Instruments and Hedging Activities Disclosure [Text Block] Income Tax Disclosure [Abstract] INCOME TAXES Income Tax Disclosure [Text Block] Effective income tax rate Effective Income Tax Rate Reconciliation, Percent Statutory rate Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent Income Tax Examination, Estimate of Possible Loss Income Tax Examination, Estimate of Possible Loss Earnings Per Share [Abstract] Reconciliation of the income used to compute basic and diluted EPS Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Schedule of Earnings Per Share, Basic, by Common Class, Including Two Class Method [Table] Schedule of Earnings Per Share Basic And Diluted by Common Class [Table] Schedule of Earnings Per Share Basic And Diluted by Common Class [Table] Antidilutive Securities [Axis] Antidilutive Securities [Axis] Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items] Schedule of Earnings Per Share Basic And Diluted by Common Class [Line Items] Schedule of Earnings Per Share Basic And Diluted by Common Class [Line Items] Earnings for basic computations Undistributed Earnings, Basic Weighted-average common shares outstanding for basic computations Weighted Average Number of Shares Outstanding, Basic Earnings for diluted computations Undistributed Earnings, Diluted Dilutive stock options and restricted stock Weighted Average Number Diluted Shares Outstanding Adjustment Weighted-average common shares outstanding for diluted computations Weighted Average Number of Shares Outstanding, Diluted Earnings per common share, Basic Earnings Per Share, Basic Earnings per common share, Diluted Earnings Per Share, Diluted Unvested shares participating in the payment of the Company's dividends declared Incremental Common Shares Attributable to Participating Nonvested Shares with Non-forfeitable Dividend Rights Unvested shares, cash dividends paid Undistributed earnings allocated to participating securities, basic Undistributed Earnings (Loss) Allocated to Participating Securities, Basic Undistributed earnings allocated to participating securities, diluted Undistributed Earnings (Loss) Allocated to Participating Securities, Diluted Antidilutive options excluded from the computation of EPS Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Other Long-Term Liabilities Schedule of Other Assets and Other Liabilities [Table Text Block] Subsequent Event [Table] Subsequent Event [Table] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Subsequent Event Type [Domain] Subsequent Event Type [Domain] Subsequent Event Subsequent Event [Member] Subsequent Event [Line Items] Subsequent Event [Line Items] Stock Repurchase Program, Authorized Amount Stock Repurchase Program, Authorized Amount Stock Repurchase Program, Remaining Authorized Repurchase Amount Stock Repurchase Program, Remaining Authorized Repurchase Amount Debt Schedule of Debt [Table Text Block] Interest Expense Interest Income and Interest Expense Disclosure [Table Text Block] ASSETS Assets [Abstract] Current assets: Assets, Current [Abstract] Cash and cash equivalents Accounts receivable, net of allowance Accounts Receivable, Net, Current Prepaid expenses and other current assets Prepaid Expense and Other Assets, Current Total current assets Assets, Current Property and equipment, net of accumulated depreciation Property, Plant and Equipment, Net Intangible assets, net of accumulated amortization Intangible Assets, Net (Excluding Goodwill) Goodwill Other long-term assets Other Assets, Noncurrent Total assets Assets LIABILITIES AND STOCKHOLDERS’ EQUITY Liabilities and Equity [Abstract] Current liabilities: Liabilities, Current [Abstract] Current portion of long-term debt Long-term Debt, Current Maturities Accounts payable and other accrued expenses Accounts Payable and Accrued Liabilities, Current Accrued compensation and benefits Other current liabilities Other Liabilities, Current Total current liabilities Liabilities, Current Long-term debt, net of current portion Long-term Debt, Excluding Current Maturities Other long-term liabilities Other Liabilities, Noncurrent Total liabilities Liabilities Commitments and contingencies (Note 18) Commitments and Contingencies Stockholders’ equity: Stockholders' Equity Attributable to Parent [Abstract] Common stock Common Stock, Value, Issued Treasury stock, at cost — 11,633,345 shares at September 30, 2017 and 7,013,777 shares at March 31, 2017 Treasury Stock, Value Additional paid-in capital Additional Paid in Capital, Common Stock Retained earnings Retained Earnings (Accumulated Deficit) Accumulated other comprehensive loss Accumulated Other Comprehensive Income (Loss), Net of Tax Total stockholders’ equity Stockholders' Equity Attributable to Parent Total liabilities and stockholders’ equity Liabilities and Equity Acquisitions Business Combination Disclosure [Text Block] Vendor payables Accounts Payable, Trade, Current Accrued expenses Accrued Liabilities, Current Total accounts payable and other accrued expenses Accrued compensation and benefits Schedule of Accrued Compensation And Benefits [Table Text Block] Schedule of Accrued Compensation And Benefits [Table Text Block] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Schedule of Accounts, Notes, Loans and Financing Receivable [Table] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Accounts Receivable Accounts Receivable [Member] Other Noncurrent Assets Other Noncurrent Assets [Member] Accounts, Notes, Loans and Financing Receivable [Line Items] Accounts, Notes, Loans and Financing Receivable [Line Items] Accounts receivable-billed Billed Contracts Receivable Accounts receivable-unbilled Unbilled Contracts Receivable Allowance for doubtful accounts Allowance for Doubtful Accounts Receivable, Current Accounts receivable, net, current Total accounts receivable, net Accounts Receivable, Net Provision for doubtful accounts Provision for Doubtful Accounts RELATED-PARTY TRANSACTIONS Related Party Transactions Disclosure [Text Block] EARNINGS PER SHARE Earnings Per Share [Text Block] BUSINESS OVERVIEW Nature of Operations [Text Block] Letter of Credit Letter of Credit [Member] Variable Rate [Axis] Variable Rate [Axis] Variable Rate [Domain] Variable Rate [Domain] London Interbank Offered Rate (LIBOR) London Interbank Offered Rate (LIBOR) [Member] Overnight Federal Funds Rate Overnight Federal Funds Rate [Member] Overnight Federal Funds Rate Base Rate Base Rate [Member] Alternative Base Rate (ABR) Alternative Base Rate (ABR) [Member] Alternative Base Rate (ABR) [Member] Range [Axis] Range [Axis] Range [Domain] Range [Domain] Minimum Minimum [Member] Maximum Maximum [Member] Term loan, face amount Debt Instrument, Face Amount Revolving credit facility, maximum borrowing capacity Line of Credit Facility, Maximum Borrowing Capacity Long-term Debt, Maximum Expanded Loan Facility Long-term Debt, Maximum Expanded Loan Facility Long-Term Debt, Maximum Expanded Loan Facility Net secured leverage ratio Debt Instrument, Net Secured Leverage Ratio, Maximum Debt Instrument, Net Secured Leverage Ratio, Maximum Long-term debt, basis spread on variable rate Debt Instrument, Basis Spread on Variable Rate Line of Credit Facility, Commitment Fee Percentage Line of Credit Facility, Commitment Fee Percentage Proceeds from lines of credit Proceeds from Lines of Credit Revolving credit facility, amount outstanding Long-term Line of Credit Quarterly periodic payment percentage, principal Debt Instrument, Quarterly Periodic Payment Percentage, Principal Debt Instrument, Quarterly Periodic Payment Percentage, Principal Debt Instrument, Interest Rate, Stated Percentage Debt Instrument, Interest Rate, Stated Percentage Debt Issuance Costs, Gross Debt Issuance Costs, Gross Deferred rent Deferred Rent Credit, Noncurrent Postretirement benefit obligations Pension and Other Postretirement and Postemployment Benefit Plans, Liabilities, Noncurrent Other Other Liabilities and Deferred Revenue, Noncurrent Total other long-term liabilities Long-term disability obligation Postemployment Benefits Liability, Noncurrent BASIS OF PRESENTATION Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] ACCOUNTS PAYABLE AND OTHER ACCRUED EXPENSES Accounts Payable and Accrued Liabilities Disclosure [Text Block] Income Statement [Abstract] Revenue Sales Revenue, Services, Net Operating costs and expenses: Costs and Expenses [Abstract] Cost of revenue Cost of Services, Direct Labor, Employee Benefits, and Overhead Cost of revenue includes direct labor, related employee benefits, and overhead. Billable expenses Billable Expenses Billable expenses include direct subcontractor expenses, travel expenses, and other expenses incurred to perform on contracts. General and administrative expenses General and Administrative Expense Total operating costs and expenses Costs and Expenses Operating income Operating Income (Loss) Interest expense Other income (expense), net Other Nonoperating Income (Expense) Income before income taxes Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest Income tax expense Income Tax Expense (Benefit) Net income Earnings per common share (Note 3): Basic (in dollars per share) Diluted (in dollars per share) Dividends declared per share Common Stock, Dividends, Per Share, Declared Accumulated Other Comprehensive Income (Loss) [Table] Accumulated Other Comprehensive Income (Loss) [Table] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Post-retirement plans Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] Derivatives designated as cash flow hedges Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] Accumulated Other Comprehensive Income (Loss) [Line Items] Accumulated Other Comprehensive Income (Loss) [Line Items] Beginning of period Other comprehensive income (loss) before reclassifications Other Comprehensive Income (Loss), before Reclassifications, Net of Tax Amounts reclassified from accumulated other comprehensive loss Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax Net current-period other comprehensive loss Other Comprehensive Income (Loss), Net of Tax End of period Other comprehensive income (loss) before reclassifications, tax Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent Long-term Debt, Current and Noncurrent [Abstract] Long-term Debt, Current and Noncurrent [Abstract] Interest rate Debt Instrument, Interest Rate, Effective Percentage Line of Credit Facility, Interest Rate at Period End Line of Credit Facility, Interest Rate at Period End Long-term Debt, Gross Long-term Debt, Gross Revolving credit facility Unamortized debt issuance costs and discount on debt Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net Long-term Debt Long-term Debt Less: Current portion of long-term debt COMMITMENTS AND CONTINGENCIES Commitments and Contingencies Disclosure [Text Block] Schedule of accumulated other comprehensive loss Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Reclassification out of accumulated other comprehensive loss to net income Reclassification out of Accumulated Other Comprehensive Income [Table Text Block] Fair Value Measurements, Recurring and Nonrecurring [Table] Fair Value Measurements, Recurring and Nonrecurring [Table] Liability Class [Axis] Liability Class [Axis] Fair Value by Liability Class [Domain] Fair Value by Liability Class [Domain] Contingent Consideration Contingent Consideration [Member] Contingent Consideration [Member] Other Noncurrent Liabilities Other Noncurrent Liabilities [Member] Measurement Frequency [Axis] Measurement Frequency [Axis] Fair Value, Measurement Frequency [Domain] Fair Value, Measurement Frequency [Domain] Fair Value, Measurements, Recurring Fair Value, Measurements, Recurring [Member] Fair Value, Hierarchy [Axis] Fair Value, Hierarchy [Axis] Fair Value, Measurements, Fair Value Hierarchy [Domain] Fair Value Hierarchy [Domain] Level 1 Fair Value, Inputs, Level 1 [Member] Level 2 Fair Value, Inputs, Level 2 [Member] Level 3 Fair Value, Inputs, Level 3 [Member] Asset Class [Axis] Asset Class [Axis] Fair Value by Asset Class [Domain] Asset Class [Domain] Cash and cash equivalents Cash [Member] Money market fund Money Market Funds [Member] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Total cash and cash equivalents Cash and Cash Equivalents, Fair Value Disclosure Derivative asset Derivative Asset, Noncurrent Total Other Assets Other Assets, Fair Value Disclosure Liabilities, Fair Value Disclosure, Recurring Liabilities, Fair Value Disclosure, Recurring Derivative liability, current Derivative Liability, Current Derivative liability, noncurrent Derivative Liability, Noncurrent Cash and cash equivalents invested in money market funds, net asset value, per share Cash And Cash Equivalents Invested In Money Market Funds, Net Asset Value, Per Share Cash And Cash Equivalents Invested In Money Market Funds, Net Asset Value, Per Share Contingent consideration, liability, noncurrent Business Combination, Contingent Consideration, Liability, Noncurrent Reclassification out of Accumulated Other Comprehensive Income [Table] Reclassification out of Accumulated Other Comprehensive Income [Table] Reclassification out of Accumulated Other Comprehensive Income [Axis] Reclassification out of Accumulated Other Comprehensive Income [Axis] Reclassification out of Accumulated Other Comprehensive Income [Domain] Reclassification out of Accumulated Other Comprehensive Income [Domain] Reclassification out of Accumulated Other Comprehensive Income Reclassification out of Accumulated Other Comprehensive Income [Member] Reclassification out of Accumulated Other Comprehensive Income [Line Items] Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] Total before tax Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Gain (Loss), before Tax Tax benefit Net of tax Net Income (Loss) Available to Common Stockholders, Basic Derivative [Table] Derivative [Table] Hedging Designation [Axis] Hedging Designation [Axis] Hedging Designation [Domain] Hedging Designation [Domain] Designated as Hedging Instrument Designated as Hedging Instrument [Member] Hedging Relationship [Axis] Hedging Relationship [Axis] Hedging Relationship [Domain] Hedging Relationship [Domain] Cash Flow Hedging Cash Flow Hedging [Member] Other Current Liabilities Other Current Liabilities [Member] Derivative Instrument [Axis] Derivative Instrument [Axis] Derivative Contract [Domain] Derivative Contract [Domain] Interest Rate Swap Interest Rate Swap [Member] Derivative [Line Items] Derivative [Line Items] Notional amount Derivative, Notional Amount Fair value of derivative assets Derivative Instruments in Hedges, Assets, at Fair Value Fair value of derivative liabilities Derivative Instruments in Hedges, Liabilities, at Fair Value Loss recognized in AOCI Derivative Instruments, Loss Recognized in Other Comprehensive Income (Loss), Effective Portion Amounts reclassified into earnings Interest Rate Cash Flow Hedge Gain (Loss) Reclassified to Earnings, Net Ineffectiveness recognized in earnings Gain (Loss) on Cash Flow Hedge Ineffectiveness, Net Estimate of amount to be reclassified over the next 12 months Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net Vesting [Axis] Vesting [Axis] Vesting [Domain] Vesting [Domain] Restricted stock units (RSUs) Restricted Stock Units (RSUs) [Member] Stock options outstanding Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Number Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Number of Shares Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value Share Price Share Price Cash purchase price paid to Aquilent shareholders Payments to Acquire Businesses, Gross Working capital and other closing adjustments Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Consideration Transferred Acquired cash on hand Cash Acquired from Acquisition Acquisition-related compensation expense Business Combination, Separately Recognized Transactions, Additional Disclosures, Acquisition Cost Expensed Total purchase consideration transferred at closing Business Combination, Consideration Transferred Document and Entity Information [Abstract] Entity Registrant Name Entity Registrant Name Entity Central Index Key Entity Central Index Key Document Type Document Type Document Period End Date Document Period End Date Amendment Flag Amendment Flag Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Entity Listings [Table] Entity Listings [Table] Non-voting common stock, Class B Common Class B [Member] Restricted common stock, Class C Common Class C [Member] Special voting common stock, Class E Common Class E [Member] Classification of common stock that has different rights than Common Class A, B or C shares, representing the voting rights that accompany options that were issued in exchange for old stock rights that existed prior to the merger with The Carlyle Group. Entity Listings [Line Items] Entity Listings [Line Items] Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Stock-based compensation expense recognized in the condensed consolidated statements of operations Schedule of Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Table Text Block] Schedule of unrecognized compensation cost Schedule of Unrecognized Compensation Cost, Nonvested Awards [Table Text Block] Accounts receivable, net Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block]