Document And Entity Information [Abstract] Document and entity information. Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Title of 12(b) Security Title of 12(b) Security Document Transition Report Document Transition Report Document Quarterly Report Document Quarterly Report Entity Registrant Name Entity Registrant Name Entity Address, Address Line One Entity Address, Address Line One Entity Address, City or Town Entity Address, City or Town Entity Address, State or Province Entity Address, State or Province Entity Address, Postal Zip Code Entity Address, Postal Zip Code Trading Symbol Trading Symbol Entity Central Index Key Entity Central Index Key Current Fiscal Year End Date Current Fiscal Year End Date Entity Filer Category Entity Filer Category Document Type Document Type Document Period End Date Document Period End Date Document Fiscal Year Focus Document Fiscal Year Focus Document Fiscal Period Focus Document Fiscal Period Focus Amendment Flag Amendment Flag Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Entity File Number Entity File Number City Area Code City Area Code Local Phone Number Local Phone Number Security Exchange Name Security Exchange Name Entity Current Reporting Status Entity Current Reporting Status Entity Interactive Data Current Entity Interactive Data Current Entity Shell Company Entity Shell Company Entity Tax Identification Number Entity Tax Identification Number Entity Small Business Entity Small Business Entity Emerging Growth Company Entity Emerging Growth Company Accounting Policies [Abstract] Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Earnings Per Share, Policy Earnings Per Share, Policy [Policy Text Block] Derivatives and Hedging, Policy Derivatives, Policy [Policy Text Block] Fair Value of Financial Instruments, Policy Fair Value of Financial Instruments, Policy [Policy Text Block] Segment Reporting, Policy Segment Reporting, Policy [Policy Text Block] Derivative Instruments and Hedging Activities Disclosure [Abstract] Fair Value Interest Rate Swaps Designated as Cash Flow Hedging Instruments Schedule of Derivatives Instruments Statements of Financial Performance and Financial Position, Location [Table Text Block] Goodwill and Intangible Assets Disclosure [Abstract] Goodwill and Intangible Assets Goodwill and Intangible Assets Disclosure [Text Block] Debt Disclosure [Abstract] Summary of Carrying Amounts of Debt Schedule of Long-term Debt Instruments [Table Text Block] Schedule of Maturities of Long-term Debt Schedule of Maturities of Long-term Debt [Table Text Block] Summary of Interest Expense Recognized Interest Expense Disclosure [Table Text Block] Tabular disclosure of components of interest expense recognized during the period related to the convertible senior notes. Components of interest expense include the contractual interest coupon, the amortization of debt issuance costs, and the amortization of the debt discount. 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 (loss) to cash flows from operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Depreciation and amortization Depreciation, Depletion and Amortization Noncash Operating Lease Expense Noncash Operating Lease Expense Portion of straight-line operating lease expense allocated to the amortization of the operating lease right of use assets. Operating Lease, Impairment Loss Operating Lease, Impairment Loss Share-based compensation Share-based Payment Arrangement, Noncash Expense Amortization of debt discount and issuance costs Amortization of Debt Issuance Costs and Discounts Goodwill, Impairment Loss Goodwill, Impairment Loss Allowances For Doubtful Accounts And Unbilled Services Accounts Receivable, Credit Loss Expense (Reversal) Deferred Income Taxes and Tax Credits Deferred Income Taxes and Tax Credits Gain (Loss) on Disposition of Business Gain (Loss) on Disposition of Business Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability Changes in operating assets and liabilities, net of divestiture: Increase (Decrease) in Operating Capital [Abstract] (Increase) decrease in receivables from clients, net Increase (Decrease) in Accounts Receivable Increase (Decrease) in Other Receivables Increase (Decrease) in Other Receivables (Increase) decrease in current income tax receivable / payable, net Increase (Decrease) in Income Taxes Payable, Net of Income Taxes Receivable (Increase) decrease in other assets Increase (Decrease) in Other Operating Assets Increase (decrease) in accounts payable and other liabilities Increase (Decrease) in Accounts Payable and Accrued Liabilities Increase (decrease) in accrued payroll and related benefits Increase (Decrease) in Employee Related Liabilities Increase (decrease) in deferred revenues Increase (Decrease) in Deferred Revenue Net cash provided by (used in) 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, net Payments to Acquire Property, Plant, and Equipment Payments to Acquire Investments Payments to Acquire Investments Investment in life insurance policies Payments for (Proceeds from) Life Insurance Policies Capitalization of internally developed software costs Payments to Develop Software 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 exercises of stock options Proceeds from Stock Options Exercised Shares redeemed for employee tax withholdings Payment, Tax Withholding, Share-based Payment Arrangement Payments for Repurchase of Common Stock Payments for Repurchase of Common Stock Proceeds from bank borrowings Proceeds from Long-term Lines of Credit Repayments of bank borrowings Repayments of Long-term Debt Payment for Contingent Consideration Liability, Financing Activities Payment for Contingent Consideration Liability, Financing Activities Net Cash Provided by (Used in) Financing Activities Net Cash Provided by (Used in) Financing Activities Effect of exchange rate changes on cash Effect of Exchange Rate on Cash and Cash Equivalents Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect Cash and cash equivalents at beginning of the period Cash and Cash Equivalents, at Carrying Value Cash and cash equivalents at end of the period Supplemental disclosure of cash flow information: Supplemental Cash Flow Information [Abstract] Non-cash investing and financing activities: Noncash Investing and Financing Items [Abstract] Property and equipment expenditures and capitalized software included in accounts payable and accrued expenses Capital Expenditures Incurred but Not yet Paid Right-of-Use Asset Obtained in Exchange for Operating Lease Liability Right-of-Use Asset Obtained in Exchange for Operating Lease Liability Equity [Abstract] Foreign currency translation adjustment, before taxes Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax Foreign currency translation adjustment, taxes Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Tax Amount of tax expense (benefit) related to, after reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature. Foreign currency translation adjustment, net of taxes Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax Unrealized gain on investment, before taxes Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, before Tax Unrealized gain on investment, tax (expense) benefit Other Comprehensive Income (Loss), Securities, Available-for-sale, Tax Unrealized gain on investment, net of taxes Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, after Tax Change in fair value, before taxes Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax Change in fair value, tax (expense) benefit Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax Change in fair value, net of taxes Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax Reclassification adjustments into earnings, before taxes Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, before Tax Reclassification adjustments into earnings, tax (expense) benefit Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Tax Reclassification adjustments into earnings, net of taxes Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax Net unrealized gain (loss), before taxes Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, before Tax, Portion Attributable to Parent Net unrealized gain (loss), tax (expense) benefit Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Tax, Portion Attributable to Parent Net unrealized gain (loss), net of taxes Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax Other comprehensive income (loss), before taxes Other Comprehensive Income (Loss), before Tax, Portion Attributable to Parent Other comprehensive income (loss), tax (expense) benefit Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent Accumulated Other Comprehensive (Income) Loss, Current period change Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Fair Value Disclosures - Convertible Debt Investment Reconciliation [Abstract] Fair Value Disclosures - Convertible Debt Investment Reconciliation [Abstract] Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Related Party [Axis] Related Party [Axis] Related Party [Domain] Related Party [Domain] Shorelight Holdings Llc [Member] Shorelight Holdings Llc [Member] Shorelight Holdings Llc [Member] Financial Instrument [Axis] Financial Instrument [Axis] Financial Instruments [Domain] Financial Instruments [Domain] Convertible senior notes Convertible Debt Securities [Member] Measurement Frequency [Axis] Measurement Frequency [Axis] Measurement Frequency [Domain] Measurement Frequency [Domain] Fair Value, Recurring [Member] Fair Value, Recurring [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] 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] Assets, Fair Value Disclosure Assets, Fair Value Disclosure Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss) Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Other Comprehensive Income (Loss) Restructuring and Related Activities [Abstract] Schedule of Restructuring Reserve by Type of Cost Schedule of Restructuring Reserve by Type of Cost [Table Text Block] Earnings Per Share [Abstract] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Antidilutive Securities [Axis] Antidilutive Securities [Axis] Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Unvested restricted stock awards Restricted Stock [Member] Warrants related to the issuance of convertible senior notes Warrant [Member] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Total anti-dilutive securities Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Reconciliation of Basic and Diluted Earnings Per Share Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Summary of Anti-dilutive Securities Excluded from Computation of Weighted Average Common Stock Equivalents Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Financing Arrangements Debt Disclosure [Text Block] Fair Value Disclosures [Abstract] Underlying Asset Class [Axis] Underlying Asset Class [Axis] Underlying Asset Class [Domain] Underlying Asset Class [Domain] Deferred Compensation Plan Assets [Member] Deferred Compensation Plan Assets [Member] Deferred Compensation Plan Assets [Member] Fair Value, Measurements, Recurring Level 2 Fair Value, Inputs, Level 2 [Member] Level 3 Fair Value, Inputs, Level 3 [Member] Convertible debt investment Derivative Instrument [Axis] Derivative Instrument [Axis] Derivative Contract [Domain] Derivative Contract [Domain] Interest Rate Swap [Member] Interest Rate Swap [Member] Liabilities: Liabilities, Fair Value Disclosure [Abstract] Fair Value, Asset/Liability Assets, Fair Value Disclosure [Abstract] Assets, fair value Financial and Nonfinancial Liabilities, Fair Value Disclosure Financial and Nonfinancial Liabilities, Fair Value Disclosure Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Balance Sheet Location [Axis] Balance Sheet Location [Axis] Balance Sheet Location [Domain] Balance Sheet Location [Domain] Accrued Liabilities [Member] Accrued Liabilities [Member] Other Noncurrent Liabilities [Member] Other Noncurrent Liabilities [Member] Derivatives, Fair Value [Line Items] Derivatives, Fair Value [Line Items] Fair Value interest rate swaps designated as cash flow hedging instruments Interest Rate Cash Flow Hedge Derivative at Fair Value, Net [Abstract] Fair Value (Derivative Asset and Liability) Interest Rate Cash Flow Hedge Derivative at Fair Value, Net Measurement Input Type [Axis] Measurement Input Type [Axis] Measurement Input Type [Domain] Measurement Input Type [Domain] Measurement Input, Discount Rate [Member] Measurement Input, Discount Rate [Member] Measurement Input, Price Volatility [Member] Measurement Input, Price Volatility [Member] Shorelight Holdings LLC Investments in notes Long-term Investments Debt Instrument, Interest Rate, Stated Percentage Debt Instrument, Interest Rate, Stated Percentage Debt Instrument, Maturity Date Debt Instrument, Maturity Date Equity Securities without Readily Determinable Fair Value, Amount Equity Securities without Readily Determinable Fair Value, Amount Debt Instrument, Measurement Input Debt Instrument, Measurement Input Restructuring Charges Restructuring and Related Activities Disclosure [Text Block] Income Tax Disclosure [Abstract] Income Taxes Income Tax Disclosure [Text Block] Other Comprehensive Income (Loss) Comprehensive Income (Loss) Note [Text Block] Derivative Instruments and Hedging Activity Derivative Instruments and Hedging Activities Disclosure [Text Block] Description of Business Nature of Operations [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] 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, Amount Revenue, Remaining Performance Obligation, Amount Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period Schedule of Restructuring and Related Costs [Table] Schedule of Restructuring and Related Costs [Table] Restructuring Type [Axis] Restructuring Type [Axis] Type of Restructuring [Domain] Type of Restructuring [Domain] Employee Severance [Member] Employee Severance [Member] Office Space Reductions [Member] Office Space Reductions [Member] Office Space Reductions [Member] Other Restructuring [Member] Other Restructuring [Member] Restructuring Cost and Reserve [Line Items] Restructuring Cost and Reserve [Line Items] Restructuring reserve Restructuring Reserve Restructuring and Related Cost, Incurred Cost Restructuring and Related Cost, Incurred Cost Payments for Restructuring Payments for Restructuring Restructuring Reserve, Accrual Adjustment Restructuring Reserve, Accrual Adjustment Fair Value of Financial Instruments Fair Value Disclosures [Text Block] Restructuring Plan [Axis] Restructuring Plan [Axis] Restructuring Plan [Domain] Restructuring Plan [Domain] Middleton, Wisconsin [Member] Middleton, Wisconsin [Member] Exit of office space in Middleton, Wisconsin Houston, Texas [Member] Houston, Texas [Member] Exit of office space in Houston, Texas LakeOswegoOregon [Member] LakeOswegoOregon [Member] LakeOswegoOregon [Member] Segments [Axis] Segments [Axis] Segments [Domain] Segments [Domain] Corporate, Non-Segment [Member] Corporate, Non-Segment [Member] Restructuring Charges [Abstract] Restructuring Charges [Abstract] Restructuring charges Restructuring Charges Restructuring and Related Cost, Accelerated Depreciation Restructuring and Related Cost, Accelerated Depreciation Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net Interest rate swap agreement, effective date Derivative, Inception Date Interest rate swap agreement, end date Derivative, Maturity Date Interest rate swap agreement for a notional amount Derivative, Notional Amount Duration of LIBOR Duration Of Libor The duration of LIBOR which is used to calculate the interest received from the counterparty. Percentage of fixed rate Interest Rate Swap Fixed Interest Rate The fixed interest rate we pay to the counterparty of the interest rate swap. Gain (loss) reclassification from accumulated OCI to income, estimate of time to transfer Derivative Instruments, Gain (Loss) Reclassification from Accumulated OCI to Income, Estimate of Time to Transfer Segment Reporting [Abstract] Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Consolidation Items [Axis] Consolidation Items [Axis] Consolidation Items [Domain] Consolidation Items [Domain] Operating Segments Operating Segments [Member] Segment Reconciling Items Segment Reconciling Items [Member] Healthcare Health Care [Member] Business Advisory Business Advisory [Member] Business Advisory [Member] Education [Member] Education [Member] Education [Member] Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Components of Segment Information Segment Reporting Information, Profit (Loss) [Abstract] Operating income (loss) Operating Income (Loss) Segment operating income as a percentage of segment revenues Operating Income Loss As Percent Of Revenues Segment operating income (loss) as percent of segment revenues. Revenue from Contract with Customer, Including Assessed Tax Revenue from Contract with Customer, Including Assessed Tax Reimbursable Revenues Reimbursable Revenues Reimbursable Revenues Total revenues and reimbursable expenses Revenues Other operating expenses Other Selling, General and Administrative Expense Gain (Loss) Related To Litigation Settlement And Other Operating Gains Gain (Loss) Related To Litigation Settlement And Other Operating Gains Amount of (gain) loss recognized in settlement of litigation and insurance claims and other operating activities. Also includes the amount of increase (decrease) in the fair value of a contingent consideration liability, including, but not limited to, differences arising upon settlement. Depreciation and amortization Depreciation, Depletion and Amortization, Nonproduction Other expense (income), net Nonoperating Income (Expense) Income from continuing operations before income tax expense Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Schedule of Goodwill [Table] Schedule of Goodwill [Table] Measurement Input, Long-term Revenue Growth Rate [Member] Measurement Input, Long-term Revenue Growth Rate [Member] Measurement Input, Long-term EBITDA margin [Domain] Measurement Input, Long-term EBITDA margin [Member] Measurement Input, Long-term EBITDA margin [Member] Measurement Input, Revenue Multiple [Member] Measurement Input, Revenue Multiple [Member] Income Statement Location [Axis] Income Statement Location [Axis] Income Statement Location [Domain] Income Statement Location [Domain] Statistical Measurement [Axis] Statistical Measurement [Axis] Statistical Measurement [Domain] Statistical Measurement [Domain] Minimum Minimum [Member] Maximum Maximum [Member] Reporting Unit [Axis] Reporting Unit [Axis] Reporting Unit [Domain] Reporting Unit [Domain] Strategy and Innovation [Member] Strategy and Innovation [Member] Strategy and Innovation [Member] Life Sciences [Member] Life Sciences [Member] Life Sciences [Member] Goodwill [Line Items] Goodwill [Line Items] Goodwill Goodwill Amortization of Intangible Assets Amortization of Intangible Assets Fair Value of Reporting Unit, Measurement Input Fair Value of Reporting Unit, Measurement Input Fair Value of Reporting Unit, Measurement Input Change in Contract with Customer, Asset [Abstract] New Accounting Pronouncements or Change in Accounting Principle [Table] New Accounting Pronouncements or Change in Accounting Principle [Table] Performance Obligation Satisfied in Prior Period [Axis] Performance Obligation Satisfied in Prior Period [Axis] Performance Obligation Satisfied in Prior Period [Axis] Performance Obligation Satisfied in Prior Period [Domain] Performance Obligation Satisfied in Prior Period [Domain] [Domain] for Performance Obligation Satisfied in Prior Period [Axis] Change in Estimated Variable Consideration [Member] Change in Estimated Variable Consideration [Member] Change in Estimated Variable Consideration [Member] Release of Allowance [Member] Release of Allowance [Member] Release of Allowance [Member] New Accounting Pronouncements or Change in Accounting Principle [Line Items] New Accounting Pronouncements or Change in Accounting Principle [Line Items] Contract with Customer, Performance Obligation Satisfied in Previous Period Contract with Customer, Performance Obligation Satisfied in Previous Period New Accounting Pronouncements or Change in Accounting Principle [Line Items] Change in Contract with Customer, Asset and Liability [Abstract] Contract with Customer, Asset, after Allowance for Credit Loss Contract with Customer, Asset, after Allowance for Credit Loss Contract Asset, Period Increase (Decrease) Increase (Decrease) in Contract with Customer, Asset Deferred revenues Deferred Revenue, Current Increase (decrease) in deferred revenues Deferred Revenue, Period Increase (Decrease) Deferred Revenue, Revenue Recognized Deferred Revenue, Revenue Recognized Statement of Financial Position [Abstract] Assets Assets [Abstract] Current assets: Assets, Current [Abstract] Cash and cash equivalents Receivables from clients, net of allowances of $8,906 and $8,907, respectively Accounts Receivable, after Allowance for Credit Loss, Current Unbilled Receivables, Current Unbilled Receivables, Current Income tax receivable Income Taxes Receivable, Current Prepaid Expense and Other Assets, Current Prepaid Expense and Other Assets, Current Total current assets Assets, Current Property and equipment, net Property, Plant and Equipment, Net Deferred Income Tax Assets, Net Deferred Income Tax Assets, Net Long-term investments Operating Lease, Right-of-Use Asset Operating Lease, Right-of-Use Asset Other non-current assets Other Assets, Noncurrent Intangible assets, net Intangible Assets, Net (Excluding Goodwill) Total assets Assets Liabilities and stockholders’ equity Liabilities and Equity [Abstract] Current liabilities: Liabilities, Current [Abstract] Accounts payable Accounts Payable, Current Accrued expenses and other current liabilities Accrued Liabilities, Current Accrued payroll and related benefits Employee-related Liabilities, Current Long-term Debt, Current Maturities Long-term Debt, Current Maturities Operating Lease, Liability, Current Operating Lease, Liability, Current Total current liabilities Liabilities, Current Non-current liabilities: Liabilities, Noncurrent [Abstract] Deferred compensation and other liabilities Deferred Compensation And Other Liabilities Aggregate carrying value, as of the balance sheet date, of the liabilities for all deferred compensation arrangements and all other non current obligations not separately disclosed in the balance sheet payable beyond one year (or the operating cycle, if longer). Long-term debt, net of current portion Long-term Debt, Excluding Current Maturities Operating Lease, Liability, Noncurrent Operating Lease, Liability, Noncurrent Deferred Income Tax Liabilities, Net Deferred Income Tax Liabilities, Net Total non-current liabilities Liabilities, Noncurrent Commitments and contingencies Commitments and Contingencies Stockholders’ equity Stockholders' Equity Attributable to Parent [Abstract] Common stock Common Stock, Value, Issued Treasury stock Treasury Stock, Value Additional paid-in capital Additional Paid in Capital, Common Stock Retained earnings Retained Earnings (Accumulated Deficit) Accumulated other comprehensive income Accumulated Other Comprehensive Income (Loss), Net of Tax Total stockholders’ equity Stockholders' Equity Attributable to Parent Total liabilities and stockholders’ equity Liabilities and Equity Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Credit Facility [Axis] Credit Facility [Axis] Credit Facility [Domain] Credit Facility [Domain] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Axis] Property, Plant and Equipment, Type [Domain] Property, Plant and Equipment, Type [Domain] Aircraft [Domain] Aircraft [Domain] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] 1.25% convertible senior notes due 2019 Convertible Debt [Member] Senior secured credit facility Senior Secured Credit Facility [Member] Senior Secured Credit Facility [Member] Promissory Note due 2024 [Member] Promissory Note due 2024 [Member] Promissory Note due 2024 [Member] Equity Components [Axis] Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Variable Rate [Axis] Variable Rate [Axis] Variable Rate [Domain] Variable Rate [Domain] LIBOR London Interbank Offered Rate (LIBOR) [Member] Base Rate [Member] Base Rate [Member] Scenario [Axis] Scenario [Axis] Scenario [Domain] Scenario [Domain] Debt Instrument [Line Items] Debt Instrument [Line Items] Aggregate principal amount Debt Instrument, Face Amount Conversion price of convertible notes Debt Instrument, Convertible, Conversion Price Effective interest rate of debt Debt Instrument, Interest Rate, Effective Percentage Common stock purchased Common Stock Underlying Convertible Senior Note And Related Transactions The number of shares of common stock underlying the convertible senior notes as well as the warrants and convertible note hedge transactions purchased concurrently with the issuance of the convertible senior notes. Common stock price per share Class of Warrant or Right, Exercise Price of Warrants or Rights Revolving Credit facility Line of Credit Facility, Current Borrowing Capacity Credit agreement expiration date Line of Credit Facility, Expiration Date Option to increase revolving credit facility Optional Increase In Revolver Optional increase in revolver. Maximum principle amount Line of Credit Facility, Maximum Borrowing Capacity Interest rate on borrowings Debt Instrument, Basis Spread on Variable Rate Percentage of other equity interests in domestic subsidiaries Percentage Of Pledged Voting Stock In Domestic Subsidiaries The percentage of pledged voting stock or other equity instruments in the domestic subsidiaries to secure the revolver and term loan. Percentage of other equity interests in foreign subsidiaries Percentage Of Pledged Voting Stock In Foreign Subsidiaries The percentage of pledged voting stock or other equity instruments in the foreign subsidiaries to secure the revolver and term loan. Maximum consolidated leverage ratio Debt Instrument, Covenant, Consolidated Leverage Ratio, Maximum Debt Instrument, Covenant, Consolidated Leverage Ratio, Maximum Debt Instrument, Covenant, Consolidated Leverage Ratio, Additional Increase Debt Instrument, Covenant, Consolidated Leverage Ratio, Additional Increase Debt Instrument, Covenant, Consolidated Leverage Ratio, Additional Increase for Certain Transactions Minimum consolidated interest coverage ratio Debt Instrument, Covenant, Interest Coverage Ratio, Minimum Debt Instrument, Covenant, Interest Coverage Ratio, Minimum Actual consolidated leverage ratio Debt Instrument, Covenant, Actual Consolidated Leverage Ratio Debt Instrument, Covenant, Actual Consolidated Leverage Ratio Actual interest coverage ratio Debt Instrument, Covenant, Actual Interest Coverage Ratio Debt Instrument, Covenant, Actual Interest Coverage Ratio Net carrying amount Long-term Debt Percentage of weighted average interest rate of borrowings Debt, Weighted Average Interest Rate Outstanding letters of credit Letters of Credit Outstanding, Amount Unused borrowing capacity under Credit Agreement Line of Credit Facility, Remaining Borrowing Capacity Repayment of Principal at Maturity Date Repayment of Principal at Maturity Date Repayment of Principal at Maturity Date Financial Assets and Liabilities Measured at Fair Value on Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Components of Other Comprehensive Income (Loss), Net of Tax Comprehensive Income (Loss) [Table Text Block] Components of Accumulated Other Comprehensive Income (Loss), Net of Tax Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months Long-term Debt, Maturities, Repayments of Principal in Year Two Long-term Debt, Maturities, Repayments of Principal in Year Two Long-term Debt, Maturities, Repayments of Principal in Year Three Long-term Debt, Maturities, Repayments of Principal in Year Three Long-term Debt, Maturities, Repayments of Principal in Year Four Long-term Debt, Maturities, Repayments of Principal in Year Four Long-term Debt, Maturities, Repayments of Principal in Year Five Long-term Debt, Maturities, Repayments of Principal in Year Five Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent Weighted average common shares outstanding – basic Weighted Average Number of Shares Outstanding, Basic Weighted average common stock equivalents Weighted Average Number Diluted Shares Outstanding Adjustment Weighted average common shares outstanding – diluted Weighted Average Number of Shares Outstanding, Diluted Net earnings (loss) per basic share: Earnings Per Share, Basic and Diluted [Abstract] Income (Loss) from Continuing Operations, Per Basic Share Income (Loss) from Continuing Operations, Per Basic Share Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Basic Share Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Basic Share Basic (USD per share) Earnings Per Share, Basic Net earnings per diluted share: Earnings Per Share, Diluted [Abstract] Income (Loss) from Continuing Operations, Per Diluted Share Income (Loss) from Continuing Operations, Per Diluted Share Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Diluted Share Discontinued Operation, Income (Loss) from Discontinued Operation, Net of Tax, Per Diluted Share Diluted (USD per share) Earnings Per Share, Diluted Receivables from Major Customer Percentage Receivables from Major Customer Percentage The percentage of combined consolidated receivables from clients, net and unbilled services, net generated by a single customer above the 10% concentration risk percentage. Number of Operating Segments Number of Operating Segments Commitments and Contingencies Disclosure [Abstract] Commitments And Contingencies [Table] Commitments And Contingencies [Table] Commitments And Contingencies [Table] Commitments And Contingencies [Line Items] Commitments And Contingencies [Line Items] Commitments And Contingencies [Line Items] Guarantees in the form of letters of credit Accelerated Share Repurchases [Table] Accelerated Share Repurchases [Table] Share Repurchase Program [Axis] Share Repurchase Program [Axis] Share Repurchase Program [Domain] Share Repurchase Program [Domain] Share Repurchase Program [Member] Share Repurchase Program [Member] Share Repurchase Program [Member] Accelerated Share Repurchases [Line Items] Accelerated Share Repurchases [Line Items] Share repurchase authorized amount Stock Repurchase Program, Authorized Amount Stock Repurchase Program, Remaining Authorized Repurchase Amount Stock Repurchase Program, Remaining Authorized Repurchase Amount Stock Repurchased and Retired During Period, Shares Stock Repurchased and Retired During Period, Shares Stock Repurchased and Retired During Period, Value Stock Repurchased and Retired During Period, Value Stock Purchase Initiated but not yet Settled, Shares Stock Purchase Initiated but not yet Settled, Shares Number of shares repurchased but not yet settled, and included in the financial statements on trade date. Share Repurchases Initiated but not yet Settled Share Repurchases Initiated but not yet Settled Share repurchases recognized during the period that have not yet been settled by the bank. Basis of Presentation Basis of Accounting [Text Block] Components of Segment Information Schedule of Segment Reporting Information, by Segment [Table Text Block] Disaggregation of Revenue Disaggregation of Revenue [Table Text Block] New Accounting Pronouncements and Changes in Accounting Principles [Abstract] New Accounting Pronouncements New Accounting Pronouncements and Changes in Accounting Principles [Text Block] Commitments, Contingencies and Guarantees Commitments Contingencies and Guarantees [Text Block] Segment Information Segment Reporting Disclosure [Text Block] Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months Estimated annual intangible assets amortization expense, Year Two Finite-Lived Intangible Assets, Amortization Expense, Year Two Estimated annual intangible assets amortization expense, Year Three Finite-Lived Intangible Assets, Amortization Expense, Year Three Estimated annual intangible assets amortization expense, Year Four Finite-Lived Intangible Assets, Amortization Expense, Year Four Estimated annual intangible assets amortization expense, Year Five Finite-Lived Intangible Assets, Amortization Expense, Year Five Statement of Stockholders' Equity [Abstract] Statement [Table] Statement [Table] Common Stock Common Stock [Member] Treasury Stock Treasury 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] Statement [Line Items] Statement [Line Items] Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Beginning Balance, shares Shares, Issued Beginning Balance Comprehensive income (loss) Comprehensive Income (Loss), Net of Tax, Attributable to Parent Issuance of common stock in connection with: Issuance Of Common Stock In Connection With [Abstract] Issuance Of Common Stock In Connection With [Abstract] Restricted stock awards, net of cancellations, shares Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures Restricted stock awards, net of cancellations Stock Issued During Period, Value, Restricted Stock Award, Net of Forfeitures Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Stock Issued During Period, Value, Stock Options Exercised Stock Issued During Period, Value, Stock Options Exercised Share-based compensation APIC, Share-based Payment Arrangement, Increase for Cost Recognition Shares redeemed for employee tax withholdings, shares Share-based Payment Arrangement, Shares Withheld for Tax Withholding Obligation Shares redeemed for employee tax withholdings Share-based Payment Arrangement, Decrease for Tax Withholding Obligation Stock Repurchased and Retired During Period, Shares Stock Repurchased and Retired During Period, Value Ending Balance, shares Ending Balance Changes in Carrying Amount of Goodwill Schedule of Goodwill [Table Text Block] Intangible Assets Schedule of Acquired Finite-Lived Intangible Assets by Major Class [Table Text Block] Schedule of Future Amortization Expense Schedule of Finite-Lived Intangible Assets, Future Amortization Expense [Table Text Block] Common stock, par value (USD per share) Common Stock, Par or Stated Value Per Share Common stock, shares authorized (shares) Common Stock, Shares Authorized Common stock, shares issued (shares) Common Stock, Shares, Issued Treasury stock, shares (shares) Treasury Stock, Shares Accounts Receivable, Allowance for Credit Loss, Current Accounts Receivable, Allowance for Credit Loss, Current Unbilled Services, Allowance for Credit Losses Unbilled Services, Allowance for Credit Losses The amount of allowance for credit losses related to unbilled services. Effective Income Tax Rate Reconciliation, Prior Year Income Taxes, Amount Effective Income Tax Rate Reconciliation, Prior Year Income Taxes, Amount Effective Income Tax Rate Reconciliation, Percent Effective Income Tax Rate Reconciliation, Percent Income tax expense (benefit) Income Tax Expense (Benefit) Income (loss) from continuing operations before taxes Effective Income Tax Rate Reconciliation, at Statutory Rate, Inclusive of State Income Tax, Percent Statutory Income Tax Rate, Inclusive of State Income Tax, Percent Statutory Income Tax Rate, Inclusive of State Income Tax, Percent Interest Expense Recognized [Table] Interest Expense Recognized [Table] Interest Expense Recognized [Table] Interest Expense Recognized [Line Items] Interest Expense Recognized [Line Items] [Line Items] for Interest Expense Recognized [Table] Interest Expense, Debt, Excluding Amortization Interest Expense, Debt, Excluding Amortization Amortization of Debt Discount (Premium) Amortization of Debt Discount (Premium) Amortization of Debt Issuance Costs Amortization of Debt Issuance Costs Interest Expense, Debt Interest Expense, Debt Earnings Per Share Earnings Per Share [Text Block] Revenue from Contract with Customer [Text Block] Revenue from Contract with Customer [Text Block] Disaggregation of Revenue [Abstract] Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] 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] Fixed-price Contract [Member] Fixed-price Contract [Member] Time-and-materials Contract [Member] Time-and-materials Contract [Member] Performance-based [Member] Performance-based [Member] Performance-based [Member] Software Service, Support and Maintenance Arrangement [Member] Software Service, Support and Maintenance Arrangement [Member] Employee Type [Axis] Employee Type [Axis] Employee Type [Axis] Employee Type [Domain] Employee Type [Domain] [Domain] for Employee Type [Axis] Full-time Billable Consultants [Member] Full-time Billable Consultants [Member] Full-time Billable Consultants [Member] Full-time Equivalents [Member] Full-time Equivalents [Member] Full-time Equivalents [Member] Timing of Transfer of Good or Service [Axis] Timing of Transfer of Good or Service [Axis] Timing of Transfer of Good or Service [Domain] Timing of Transfer of Good or Service [Domain] Transferred over Time [Member] Transferred over Time [Member] Transferred at Point in Time [Member] Transferred at Point in Time [Member] Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Statement of Comprehensive Income [Abstract] Revenues and reimbursable expenses: Revenues [Abstract] Direct costs and reimbursable expenses (exclusive of depreciation and amortization shown in operating expenses): Direct Operating Costs [Abstract] Cost of Goods and Service, Excluding Depreciation, Depletion, and Amortization Cost of Goods and Service, Excluding Depreciation, Depletion, and Amortization Cost, Depreciation and Amortization Cost, Depreciation and Amortization Reimbursable Expense Reimbursable Expense Reimbursable Expense Total direct costs and reimbursable expenses Cost of Revenue Operating expenses and other losses (gains), net Operating Expenses [Abstract] Selling, general and administrative expenses Selling, General and Administrative Expense Total operating expenses and other losses (gains), net Operating Expenses Operating income (loss) Other income (expense), net: Nonoperating Income (Expense) [Abstract] Interest expense, net of interest income Interest Income (Expense), Nonoperating, Net Other income (expense), net Other Nonoperating Income (Expense) Total other income (expense), net Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent Net income (loss) Net income (loss) from continuing operations Basic (USD per share) Earnings Per Share, Diluted Weighted average shares used in calculating earnings (loss) per share: Weighted Average Number of Shares Outstanding, Diluted [Abstract] Weighted average common shares outstanding – diluted Net income (loss) Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract] Foreign currency translation adjustments, net of tax Unrealized gain (loss) on investment, net of tax Unrealized loss on cash flow hedging instruments, net of tax Other comprehensive income (loss) Long-term Debt, Current Maturities Foreign Currency Translation Adjustments, Beginning balance Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax Foreign Currency Translation Adjustments, Ending balance Net Unrealized Gain (Loss) on Investment, Beginning balance AOCI, Debt Securities, Available-for-sale, Adjustment, after Tax Net Unrealized Gain (Loss) on Investment, Ending balance Net Unrealized Losses on Derivatives, Beginning balance Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax Net Unrealized Losses on Derivatives, Ending balance Accumulated Other Comprehensive Income (Loss), Beginning balance Accumulated Other Comprehensive Income (Loss), Ending balance Schedule of Finite-Lived Intangible Assets [Table] Schedule of Finite-Lived Intangible Assets [Table] Business Acquisition [Axis] Business Acquisition [Axis] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] 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 [Member] Customer Relationships [Member] Trade Names [Member] Trade Names [Member] Technology And Software [Member] Technology-Based Intangible Assets [Member] Noncompete Agreements [Member] Noncompete Agreements [Member] Customer Contracts [Member] Customer Contracts [Member] Finite-Lived Intangible Assets [Line Items] Finite-Lived Intangible Assets [Line Items] Intangible assets Finite-Lived Intangible Assets, Net [Abstract] Useful Life (in years) Finite-Lived Intangible Asset, Useful Life Gross Carrying Amount Finite-Lived Intangible Assets, Gross Accumulated Amortization Finite-Lived Intangible Assets, Accumulated Amortization Goodwill Goodwill, Gross Accumulated impairment losses Goodwill, Impaired, Accumulated Impairment Loss Goodwill, Impairment Loss Goodwill, Foreign Currency Translation Gain (Loss) Goodwill, Foreign Currency Translation Gain (Loss) Goodwill, net ending balance