Restricted stock units and awards (in shares) Incremental Common Shares Attributable To Restricted Stock Units And Awards Incremental common shares attributable to restricted stock awards. Cash equivalents included in funds held for clients Cash Equivalents Included In Funds Held For Clients Cash equivalents included in funds held for clients. Stock options (in shares) Incremental Common Shares Attributable To Stock Options Incremental common shares attributable to stock options. Exercised or released (in shares) Vested (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Fair Value Hierarchy and NAV [Domain] Fair Value Hierarchy and NAV [Domain] Net income Net income Net Income (Loss) Attributable to Parent Operating lease right-of-use assets, net Operating Lease, Right-of-Use Asset Accrued personnel costs Employee-related Liabilities, Current Transaction and integration related costs Business Combination, Acquisition Related Costs Statistical Measurement [Domain] Statistical Measurement [Domain] Other intangibles Other Intangible Assets [Member] Fair market value adjustment Available For Sale Securities Debt Securities Fair Market Value Adjustment Available-for-sale securities, debt securities, fair market value adjustment. Security Exchange Name Security Exchange Name Client fund obligations Client Fund Obligations Client fund obligations. Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Additional paid in capital Additional Paid in Capital, Common Stock Other current liabilities acquired Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Other Other non-current assets Other Assets, Noncurrent Debt Securities, Available for Sale [Roll Forward] Debt Securities, Available for Sale [Roll Forward] Debt Securities, Available for Sale Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Segments [Axis] Segments [Axis] Maximum stock based compensation awards granted under the plan (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant 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 Entity File Number Entity File Number Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] Schedule of Changes in the Allowance for Doubtful Accounts on Accounts Receivable Schedule Of Changes In Allowance For Doubtful Accounts [Table Text Block] Schedule of changes in allowance for doubtful accounts. Income taxes payable Increase (Decrease) in Income Taxes Payable Change in fair value of contingencies Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings Fair value measurements, inter-transfers between levels Fair Value Measurements Inter Transfers Between Levels Fair value measurements inter transfers between levels. Operating lease right-of-use asset acquired Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Operating Lease Right-of-Use Assets Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Operating Lease Right-of-Use Assets Summary of Investments Debt Securities, Available-for-sale [Table Text Block] Change in funds held for clients Increase Decrease In Funds Held For Client Investing Activities Increase (decrease) in funds held for client investing activities. Commitments And Contingencies [Table] Commitments And Contingencies [Table] Commitments and contingencies. Subsequent Event Type [Domain] Subsequent Event Type [Domain] Identifiable intangible assets acquired Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill Business Acquisition, Contingent Consideration [Line Items] Business Acquisition, Contingent Consideration [Line Items] Acquired finite-lived intangible assets, useful life Acquired Finite-lived Intangible Assets, Weighted Average Useful Life Certified Deposits and Other Depository Assets Certified Deposits And Other Depository Assets [Member] Certified deposits and other depository assets. Share based awards excluded from the calculation of diluted earnings per share (in shares) Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Accounting, tax, advisory and consulting Accounting Tax Advisory And Consulting [Member] Accounting, tax, advisory and consulting. Liability Class [Axis] Liability Class [Axis] Subsequent Events [Abstract] Schedule of Business Acquisitions by Acquisition, Contingent Consideration [Table] Schedule of Business Acquisitions by Acquisition, Contingent Consideration [Table] Business Combination and Asset Acquisition [Abstract] Business Acquisition [Axis] Business Acquisition [Axis] 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 Maturities Proceeds from Maturities, Prepayments and Calls of Debt Securities, Available-for-sale Unrealized loss on available-for-sale securities, income tax expense (benefit) OCI, Debt Securities, Available-for-Sale, Gain (Loss), after Adjustment, Tax Number of practice groups Number Of Practice Groups Number of practice groups. Award Type [Domain] Award Type [Domain] Local Phone Number Local Phone Number Contingent Consideration Schedule of Business Acquisitions by Acquisition, Contingent Consideration [Table Text Block] ASSETS Assets [Abstract] National Practices National Practices [Member] National practices. Exercisable at end of period (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number Granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Outstanding at beginning of period (in shares) Outstanding at end of period (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Retained Earnings Retained Earnings [Member] Non-current liabilities: Liabilities, Noncurrent [Abstract] Cash settlement paid Payments for Previous Acquisition Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Series of Individually Immaterial Business Acquisitions Series of Individually Immaterial Business Acquisitions [Member] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] Core benefits and insurance services Core Benefits And Insurance Services [Member] Core benefits and insurance services. Investments, All Other Investments [Abstract] Investments, All Other Investments [Abstract] Accounts receivable, net Increase (Decrease) in Accounts Receivable CBIZ Operations and a former employee of CBIZ MMP C B I Z Operations And Former Employee Of C B I Z M M P [Member] CBIZ Operations and a former employee of CBIZ MMP Member. Indirect repurchase of shares for minimum tax withholding (in shares) Share-based Payment Arrangement, Shares Withheld for Tax Withholding Obligation Commitments and Contingencies Disclosure [Abstract] Commitments and Contingencies Disclosure [Abstract] Weighted average rates Debt, Weighted Average Interest Rate Schedule of Segment Reporting Information, by Segment [Table] Schedule of Segment Reporting Information, by Segment [Table] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table] Number of interest rate swaps outstanding Number of Interest Rate Derivatives Held Number of business units of the company Number of Operating Segments Available funds under credit facility Line of Credit Facility, Remaining Borrowing Capacity Interest rate swap, fixed interest rate Derivative, Fixed Interest Rate Net income (in dollars per share) Earnings Per Share, Basic Contingent purchase price liabilities Business Combination, Contingent Consideration, Liability, Current Outstanding at beginning of period (in shares) Outstanding at end of period (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Beginning balance – January 1 Ending balance - June 30 Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability Value Debt issuance costs Unamortized Debt Issuance Expense Interest expense Total Interest Expense, Debt Summary of Disaggregation of Revenue by Source Disaggregation of Revenue [Table Text Block] Stock options Stock or Unit Option Plan Expense Achievement of an earnings per share target Share Based Compensation Arrangement By Share Based Payment Award Equity Instruments Other Than Options Percentage Of Target Earnings Per Share Share based compensation arrangement by share based payment award equity instruments other than options percentage of target earnings per share. Diluted: Diluted Earnings Per Share, Diluted [Abstract] Intangibles Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles Indirect repurchase of shares for minimum tax withholding Share-based Payment Arrangement, Decrease for Tax Withholding Obligation Fair value, asset Derivative Asset, Fair Value, Gross Asset License bonds outstanding amount License Bonds Outstanding Amount License bonds outstanding. Achievement of total growth in revenue Share Based Compensation Arrangements By Share Based Payment Award Performance Stock Of Total Growth In Revenue Share based compensation arrangements by share based payment award performance stock of total growth in revenue. Assets of deferred compensation plan Deferred compensation plan assets Deferred Compensation Plan Assets Total recorded purchase price Business Combination, Consideration Transferred Provision Accounts Receivable, Credit Loss Expense (Reversal) Continuing operations (in dollars per share) Diluted earnings per share from continuing operations (in dollars per share) Income (Loss) from Continuing Operations, Per Diluted Share Plan Name [Axis] Plan Name [Axis] Level 1 Fair Value, Inputs, Level 1 [Member] Cash flows from investing activities: Net Cash Provided by (Used in) Investing Activities [Abstract] Fair Value by Liability Class [Domain] Fair Value by Liability Class [Domain] Other, net Other Operating Activities, Cash Flow Statement 2019 Plan Two Thousand Nineteen Stock Omnibus Incentive Plan [Member] Two thousand nineteen stock omnibus incentive plan. Entity Small Business Entity Small Business Contingent shares (in shares) Incremental Common Shares Attributable to Dilutive Effect of Contingently Issuable Shares Total liabilities and stockholders’ equity Liabilities and Equity Contingent purchase price liabilities Contingent Purchase Price Liabilities At Fair Value Contingent purchase price liabilities. Discontinued operations (in dollars per share) Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share Exercised or released (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Restricted cash Restricted Cash Accounts payable Increase (Decrease) in Accounts Payable Additions from business acquisitions Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Purchases Interest rate swaps Interest rate swaps Interest Rate Swap [Member] Short-term Debt, Type [Domain] Short-term Debt, Type [Domain] Earnings Per Share Earnings Per Share [Text Block] Share repurchases Share repurchases, value Treasury Stock, Value, Acquired, Cost Method Entity Interactive Data Current Entity Interactive Data Current Accounting Changes and Error Corrections [Abstract] Accounting Changes and Error Corrections [Abstract] Stock options exercised Stock Issued During Period, Value, Stock Options Exercised Minimum Minimum [Member] Adjustment to contingent earnout liability Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability Gross margin Gross Profit Balance Sheet Location [Domain] Balance Sheet Location [Domain] Entity Common Stock, Shares Outstanding Entity Common Stock, Shares Outstanding Contingent purchase price liabilities Contingent Purchase Price Payable [Member] Contingent purchase price payable. Entity Address, State or Province Entity Address, State or Province Damages sought amount Loss Contingency, Damages Sought, Value Managed networking, hardware services Managed Networking And Hardware Services [Member] Managed networking and hardware services. Business acquisitions Stock Issued During Period, Value, Acquisitions Current liabilities: Liabilities, Current [Abstract] Corporate general and administrative expenses Corporate general and administrative expenses General and Administrative Expense Business acquisitions and purchases of client lists, net of cash acquired Payments to Acquire Businesses, Net of Cash Acquired Debt and Financing Arrangements Debt Disclosure [Text Block] Exercisable at end of period (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price Other line of credit Line of Credit [Member] Employee Stock Plans Share-based Payment Arrangement [Text Block] Level 3 Fair Value, Inputs, Level 3 [Member] Accounting Policies [Abstract] Accounting Policies [Abstract] Derivative Instrument [Axis] Derivative Instrument [Axis] Other assets acquired Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets Benefits and Insurance Services Benefits And Insurance Services [Member] Benefits and insurance services. Outstanding letters of credit Letters of credit outstanding Letters of Credit Outstanding, Amount Document Transition Report Document Transition Report Income from continuing operations Income from continuing operations Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent Common stock Common Stock, Value, Issued Funds held for clients Funds Held for Clients Disaggregation of Revenue [Line Items] Disaggregation of Revenue [Line Items] Total other (expense) income, net Nonoperating Income (Expense) Outstanding at beginning of period (in dollars per share) Outstanding at end of period (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 Unaudited Interim Financial Statements Basis of Accounting, Policy [Policy Text Block] Performance share units Performance Shares [Member] Total non-current assets Assets, Noncurrent Subsequent Event [Table] Subsequent Event [Table] Accumulated other comprehensive income (loss) Accumulated Other Comprehensive Income (Loss), Net of Tax Entity Emerging Growth Company Entity Emerging Growth Company Allowance for doubtful accounts Balance at beginning of period Allowance for doubtful accounts Accounts Receivable, Allowance for Credit Loss, Current Income taxes payable Accrued Income Taxes, Noncurrent Business Combinations Business Combination Disclosure [Text Block] Summary of Outstanding Interest Rate Swaps Schedule of Interest Rate Derivatives [Table Text Block] Receivables [Abstract] Receivables [Abstract] Schedule of Stock Options, Restricted Stock Units and Awards, and Performance Share Units Award Activity Share-based Payment Arrangement, Activity [Table Text Block] Unrealized gain on interest rate swaps, income tax expense (benefit) Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, Tax Antidilutive Securities, Name [Domain] Antidilutive Securities, Name [Domain] Cover [Abstract] Cover [Abstract] Class of Stock [Axis] Class of Stock [Axis] Operating cash flows used in discontinued operations Cash Provided by (Used in) Operating Activities, Discontinued Operations Unbilled revenue, at net realizable value Unbilled Receivables, Current Comprehensive income: Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract] Revenue Revenue from Contract with Customer, Excluding Assessed Tax Schedule of Available-for-sale Securities [Table] Schedule of Available-for-sale Securities [Table] Accounts Receivable, Net Loans, Notes, Trade and Other Receivables Disclosure [Text Block] Description of Business Description Of Business Policy [Policy Text Block] Description Of Business Policy Consolidation Items [Domain] Consolidation Items [Domain] Equity [Abstract] Equity [Abstract] Fair Value Hierarchy and NAV [Axis] Fair Value Hierarchy and NAV [Axis] Document Quarterly Report Document Quarterly Report Interest rate swap, May 2022 expiration Interest Rate Swap, May 2022 Expiration [Member] Interest Rate Swap, May 2022 Expiration Common Stock Common Stock [Member] Segment Disclosures Segment Reporting Disclosure [Text Block] Operating income Operating Income (Loss) Debt Securities, Available-for-sale [Line Items] Debt Securities, Available-for-sale [Line Items] Operating lease liabilities Operating Lease, Liability, Current Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity [Roll Forward] Document Fiscal Year Focus Document Fiscal Year Focus Stock-based compensation expense Share-based Payment Arrangement, Noncash Expense Additional Paid-In Capital Additional Paid-in Capital [Member] Cash and cash equivalents Cash and Cash Equivalents, at Carrying Value Long-term Debt, Type [Domain] Long-term Debt, Type [Domain] Treasury Shares Treasury Stock [Member] Deferred compensation plan obligations Deferred compensation plan liabilities Deferred Compensation Liability, Classified, Noncurrent Purchases Payments to Acquire Debt Securities, Available-for-sale Notional amount Derivative, Notional Amount Other (expense) income, net Other (expense) income, net Other Nonoperating Income (Expense) Other liabilities Increase (Decrease) in Other Operating Liabilities Other, net Payments for (Proceeds from) Other Investing Activities Additions to property and equipment Payments to Acquire Property, Plant, and Equipment Other current liabilities Other Liabilities, Current Maximum Maximum [Member] Share-based Payment Arrangement [Abstract] Share-based Payment Arrangement [Abstract] Restricted Stock Units and Awards Restricted Stock Units And Awards [Member] Restricted stock units and awards. Total liabilities Liabilities Award Type [Axis] Award Type [Axis] Granted (in dollars per share) Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price Cash flows from financing activities: Net Cash Provided by (Used in) Financing Activities [Abstract] Consolidation Items [Axis] Consolidation Items [Axis] Total stockholders’ equity Beginning balance Ending balance Stockholders' Equity Attributable to Parent City Area Code City Area Code Settlement of contingent purchase price liabilities Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Settlements Entity Address, City or Town Entity Address, City or Town Payment for acquisition of treasury stock Payments for Repurchase of Common Stock Stock-based compensation APIC, Share-based Payment Arrangement, ESPP, Increase for Cost Recognition STOCKHOLDERS' EQUITY Stockholders' Equity Attributable to Parent [Abstract] Gain Recognized in AOCI, net of tax Net unrealized gain (loss) on interest rate swaps, net of income taxes Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax, Parent Balance Sheet Location [Axis] Balance Sheet Location [Axis] Other Comprehensive Income Comprehensive Income (Loss) Note [Text Block] Operating lease liabilities Operating Lease, Liability, Noncurrent Non-current assets: Assets, Noncurrent [Abstract] Accrued personnel costs Increase (Decrease) in Employee Related Liabilities Operating lease liability acquired - current Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Operating Lease Liability Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities, Operating Lease Liability Range of effective rates Debt Instrument, Interest Rate, Effective Percentage Dilutive Securities Included And Antidilutive Securities Excluded From Computation Of Earnings Per Share [Table] Dilutive Securities Included And Antidilutive Securities Excluded From Computation Of Earnings Per Share [Table] Dilutive securities included and antidilutive securities excluded from computation of earnings per share. Total net assets acquired Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net Retained earnings Retained Earnings (Accumulated Deficit) Operating segments Operating Segments [Member] Share-based payment arrangement (in shares) Share-based Payment Arrangement [Member] Derivatives, Fair Value [Line Items] Derivatives, Fair Value [Line Items] Litigation Case [Domain] Litigation Case [Domain] Statement of Stockholders' Equity [Abstract] Statement of Stockholders' Equity [Abstract] Entity Filer Category Entity Filer Category Trade accounts receivable Billed Contracts Receivable Entity Registrant Name Entity Registrant Name Change in Level 3 Fair Values of Contingent Purchase Price Liabilities Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Table Text Block] Accounts receivable acquired Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables New Accounting Pronouncements Accounting Standards Update and Change in Accounting Principle [Text Block] Other non-current assets Other Noncurrent Assets [Member] Proceeds from exercise of stock options Proceeds from Stock Options Exercised Finite-Lived Intangible Assets by Major Class [Axis] Finite-Lived Intangible Assets by Major Class [Axis] Income tax expense Income Tax Expense (Benefit) Accounts receivable, net Accounts receivable, net Accounts Receivable, after Allowance for Credit Loss, Current Amendment Flag Amendment Flag Equity Components [Axis] Equity Components [Axis] Entity Tax Identification Number Entity Tax Identification Number Fair Value Disclosures [Abstract] Fair Value Disclosures [Abstract] Antidilutive Securities [Axis] Antidilutive Securities [Axis] Investment Type [Axis] Investment Type [Axis] Summary of Effects of Interest Rate Swap Summary Of Effects Of Interest Rate Swaps [Table Text Block] Summary Of Effects Of Interest Rate Swaps Document Fiscal Period Focus Document Fiscal Period Focus Total current assets Assets, Current Current assets before funds held for clients Current Assets Before Funds Held For Clients Current assets before funds held for clients. Disaggregation of Revenue [Table] Disaggregation of Revenue [Table] Loss Reclassified from AOCL into Expense Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax Summary of Segment Information Schedule of Segment Reporting Information, by Segment [Table Text Block] Other depository assets Other Assets, Fair Value Disclosure 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] Statement of Financial Position [Abstract] Statement of Financial Position [Abstract] Contingent purchase price liabilities Business Combination, Contingent Consideration, Liability, Noncurrent Product and Service [Axis] Product and Service [Axis] Accounts Receivable, Allowance for Credit Loss [Roll Forward] Accounts Receivable, Allowance for Credit Loss [Roll Forward] Equity Component [Domain] Equity Component [Domain] Restricted stock units and awards and Performance share units (in shares) Shares Issued, Shares, Share-based Payment Arrangement, after Forfeiture Statement [Line Items] Statement [Line Items] Litigation Case [Axis] Litigation Case [Axis] Total transaction price Transaction Price Transaction price. Bank debt Outstanding balance under applicable credit facility Long-term Line of Credit, Noncurrent Business acquisitions (in shares) Stock Issued During Period, Shares, Acquisitions Stock Option Weighted Average Exercise Price Per Share Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract] Bad debt expense, net of recoveries Provision For Doubtful Accounts Net Of Recoveries Provision for doubtful accounts net of recoveries. Commitments And Contingencies [Line Items] Commitments And Contingencies [Line Items] Commitments and contingencies. Purchases of client fund investments Payments to Acquire Investments Loss from discontinued operations, net of tax Discontinued Operation, Income (Loss) from Discontinued Operation During Phase-out Period, Net of Tax Restricted stock units and awards and Performance share units Shares Issued, Value, Share-based Payment Arrangement, after Forfeiture Short-term Debt, Type [Axis] Short-term Debt, Type [Axis] LIABILITIES Liabilities [Abstract] Fair value at beginning of period Fair value at end of period Available-for-sale debt securities Debt Securities, Available-for-sale Maximum potential contingent consideration Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High Proceeds from the sales and maturities of client fund investments Proceeds from Sale, Maturity and Collection of Investments Net expense Business Combination Contingent Consideration Liability Other Adjustments Based On Projected Future Results Of Acquisition Business combination contingent consideration liability other adjustments based on projected future results of acquisition. Debt Disclosure [Abstract] Debt Disclosure [Abstract] Income from continuing operations before income tax    expense Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest Level 2 Fair Value, Inputs, Level 2 [Member] Summary of Recognized Interest Expense Interest Expense Table [Table Text Block] Cash and non-cash interest expense related to the Convertible Notes for the periods presented. Corporate and Other Corporate, Non-Segment [Member] Segment Reporting [Abstract] Segment Reporting [Abstract] Unsecured credit facility Unsecured Long-term Debt, Noncurrent Payment of contingent consideration for acquisitions Payment Of Contingent Consideration Of Acquisitions Payment of contingent consideration for acquisitions. Par value of available-for-sale debt securities Debt Securities, Available-for-sale, Amortized Cost Use of Estimates Use of Estimates, Policy [Policy Text Block] Computation of Basic and Diluted Earnings Per Share from Continuing Operations Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross Other comprehensive income, net of tax Other comprehensive income Total other comprehensive income Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent Schedule of Stock-Based Compensation Awards Share-based Payment Arrangement, Expensed and Capitalized, Amount [Table Text Block] Title of 12(b) Security Title of 12(b) Security Total assets Assets Deferred income taxes Deferred Income Taxes and Tax Credits Plan Name [Domain] Plan Name [Domain] Numerator: Net Income (Loss) Attributable to Parent [Abstract] Document Type Document Type Product and Service [Domain] Product and Service [Domain] Schedule of Accounts Receivable, Net Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block] Derivative Contract [Domain] Derivative Contract [Domain] Changes in Accounting Policies Changes In Accounting Policy [Policy Text Block] Changes In Accounting Policy Recorded contingent consideration Business Combination, Contingent Consideration, Liability Total non-current liabilities Liabilities, Noncurrent Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Summary of Unsecured Credit Facility Schedule of Line of Credit Facilities [Table Text Block] Financial Services Financial Services Financial Services [Member] Financial services. Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Outstanding line of credit Short-term Debt Net cash used in operating activities Net Cash Provided by (Used in) Operating Activities Fair Value, Recurring and Nonrecurring [Table] Fair Value, Recurring and Nonrecurring [Table] Notional amount, liability Derivative Liability, Notional Amount Schedule of Long-term Debt Instruments [Table] Schedule of Long-term Debt Instruments [Table] Subsequent Event [Line Items] Subsequent Event [Line Items] Basic: Basic Earnings Per Share, Basic [Abstract] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] Basic weighted average shares outstanding (in shares) Weighted average common shares outstanding (in shares) Weighted Average Number of Shares Outstanding, Basic Net income (in dollars per share) Earnings Per Share, Diluted Business Combination Segment Allocation [Line Items] Business Combination Segment Allocation [Line Items] Segments [Domain] Segments [Domain] Payment of bank debt Repayments of Long-term Lines of Credit Shares issued (number) Number Of Common Shares Issued Number of common shares issued. Charge-offs, net of recoveries Allowance For Doubtful Accounts Receivable Write Offs And Net Of Recoveries Allowance for doubtful accounts receivable write offs and net of recoveries. Subsequent Events Subsequent Events [Text Block] Comprehensive income Comprehensive Income (Loss), Net of Tax, Attributable to Parent Operating expenses Operating expenses (income) Cost of Revenue Net cash provided by (used in) financing activities Net Cash Provided by (Used in) Financing Activities Treasury stock Treasury Stock, Value Denominator: Weighted Average Number of Shares Outstanding, Diluted [Abstract] Deferred income taxes, net Deferred Income Tax Liabilities, Net Performance share units, vesting period Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Share-based compensation arrangement by share-based payment award, remaining contractual term Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Outstanding, Weighted Average Remaining Contractual Terms Other non-current liability Other Noncurrent Liabilities [Member] Summary of Other Comprehensive Income and Tax Impact Comprehensive Income (Loss) [Table Text Block] Business Acquisition, Acquiree [Domain] Business Acquisition, Acquiree [Domain] Fixed assets acquired Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment Continuing operations (in dollars per share) Basic earnings per share from continuing operations (in dollars per share) Income (Loss) from Continuing Operations, Per Basic Share Fair Value Measurements Fair Value Disclosures [Text Block] Accounts payable Accounts Payable, Current Depreciation and amortization expense Depreciation, Depletion and Amortization Summary of Assets and Liabilities Measured at Fair Value on a Recurring Basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Proceeds from bank debt Proceeds from Long-term Lines of Credit Total Business Combination, Aggregated Goodwill And Intangible Assets Acquired Business Combination, Aggregated Goodwill And Intangible Assets Acquired Dilutive Securities Included And Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items] Dilutive Securities Included And Antidilutive Securities Excluded From Computation Of Earnings Per Share [Line Items] Dilutive securities included and antidilutive securities excluded from computation of earnings per share. Accumulated Other Comprehensive (Loss) Income AOCI Attributable to Parent [Member] Document Period End Date Document Period End Date Proceeds from sales of divested operations Proceeds from Divestiture of Businesses Entity Central Index Key Entity Central Index Key Interest rate swap, June 2023 expiration Interest Rate Swap, June 2023 Expiration [Member] Interest Rate Swap, June 2023 Expiration Restricted stock units and awards Restricted Stock or Unit Expense Stock Option Activity Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Property and equipment, net Property, Plant and Equipment, Net Other non-current liabilities Other Liabilities, Noncurrent Share repurchases (in shares) Treasury Stock, Shares, Acquired Current liabilities before client fund obligations Current Liabilities Before Client Fund Obligations Current liabilities before client fund obligations. Other Other Interest Expense [Member] Other interest expense. Debt Instrument [Line Items] Debt Instrument [Line Items] Trading Symbol Trading Symbol Earnings per share: Earnings Per Share [Abstract] Annual revenue Business Acquisition, Pro Forma Revenue Foreign currency translation Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Parent Other assets Increase (Decrease) in Other Operating Assets Changes in client funds obligations Net Increase Decrease In Client Funds Obligations Net (decrease) increase in client funds obligations. Other current liability Other Current Liabilities [Member] Redemptions Proceeds from Sale of Debt Securities, Available-for-sale Discontinued operations (in dollars per share) Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share Outstanding at beginning of period (in dollars per share) Outstanding at end of period (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Total long-term debt Long-term Debt, Excluding Current Maturities Interest rate swaps Interest Rate Derivatives, at Fair Value, Net Total stock-based compensation expense Share-based Payment Arrangement, Expense Goodwill and other intangible assets, net Intangible Assets, Net (Including Goodwill) Entity Current Reporting Status Entity Current Reporting Status Restricted Stock Units and Awards Weighted Average Grant Date Fair Value Performance Share Units Award 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] Interest rate swap, April 2025 expiration Interest Rate Swap, April 2025 Expiration [Member] Interest Rate Swap, April 2025 Expiration National practices consulting National Practices Consulting [Member] National practices consulting. Investments [Domain] Investments [Domain] Total accounts receivable Accounts Receivable, before Allowance for Credit Loss, Current Restricted cash Restricted Cash, Current Cash, cash equivalents and restricted cash at beginning of year Cash, cash equivalents and restricted cash at end of period Total cash, cash equivalents and restricted cash Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Beginning balance (in shares) Ending balance (in shares) Shares, Issued Reconciliation of cash, cash equivalents and restricted cash to the   Condensed Consolidated Balance Sheets: Reconciliation Of Cash Cash Equivalents And Restricted Cash To Consolidated Balance Sheet [Abstract] Reconciliation of cash, cash equivalents and restricted cash to the Consolidated Balance Sheets. Statement of Comprehensive Income [Abstract] Statement of Comprehensive Income [Abstract] Current assets: Assets, Current [Abstract] Other, net Proceeds from (Payments for) Other Financing Activities Percentage of initial grant Share Based Compensation Arrangements By Share Based Payment Award Performance Stock Percentage Of Initial Grant Share based compensation arrangements by share based payment award performance stock percentage of initial grant. Entity Address, Postal Zip Code Entity Address, Postal Zip Code Stock options exercised (in shares) Exercised or released (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Change in bond premium Increase Decrease In Bond Premium Increase (Decrease) in bond premium. Diluted weighted average shares outstanding (in shares) Diluted weighted average common shares outstanding (in shares) Weighted Average Number of Shares Outstanding, Diluted Business Combination, Segment Allocation [Table] Business Combination, Segment Allocation [Table] Segment Allocation Business Combination, Segment Allocation [Table Text Block] Long-term Debt, Type [Axis] Long-term Debt, Type [Axis] 2018 Credit Facility 2018 credit facility Two Thousand And Eighteen Credit Facility [Member] Two thousand and eighteen credit facility. Statement of Cash Flows [Abstract] Statement of Cash Flows [Abstract] Other income (expense): Nonoperating Income (Expense) [Abstract] Operating lease liability acquired - noncurrent Business Combination, Recognized Identifiable Asset Acquired and Liability Assumed, Lease Obligation Finite-Lived Intangible Assets, Major Class Name [Domain] Finite-Lived Intangible Assets, Major Class Name [Domain] Entity Address, Address Line One Entity Address, Address Line One Net cash (used in) provided by investing activities Net Cash Provided by (Used in) Investing Activities Entity Address, Address Line Two Entity Address, Address Line Two Changes in assets and liabilities, net of acquisitions and divestitures: Increase (Decrease) in Operating Capital [Abstract] Notional amount, asset Derivative Asset, Notional Amount Net unrealized loss on available-for-sale securities, net of income taxes Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax, Portion Attributable to Parent Cash flows from operating activities: Net Cash Provided by (Used in) Operating Activities [Abstract] Exercised or released (in dollars per share) 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 Basis of Consolidation Consolidation, Policy [Policy Text Block] Entity Shell Company Entity Shell Company Total current liabilities Liabilities, Current Indirect repurchase of shares for minimum tax withholding Payment, Tax Withholding, Share-based Payment Arrangement Class of Stock [Domain] Class of Stock [Domain] Cash paid Payments to Acquire Businesses, Gross Performance share units Performance Share Units Performance share units. Revolving loan commitment Line of Credit Facility, Maximum Borrowing Capacity Segment Reporting Information [Line Items] Segment Reporting Information [Line Items] Current Fiscal Year End Date Current Fiscal Year End Date Financial Instruments Financial Instruments Disclosure [Text Block] Operating cash flows used in continuing operations Net Cash Provided by (Used in) Operating Activities, Continuing Operations Aggregated Consideration And Preliminary Purchase Price Allocation Business Acquisition, Aggregated Consideration And Preliminary Purchase Price Allocation [Table Text Block] Business Acquisition, Aggregated Consideration And Preliminary Purchase Price Allocation Statement [Table] Statement [Table] Other current assets Other Assets, Current Client list Customer Lists [Member] Restricted Stock Units and Awards Activity Performance Share Units Award Activity Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward] New Accounting Pronouncements New Accounting Pronouncements, Policy [Policy Text Block] Statistical Measurement [Axis] Statistical Measurement [Axis] Fair value, liability Derivative Liability, Fair Value, Gross Liability Subsequent Event Subsequent Event [Member] Non-core benefits and insurance services Non Core Benefits And Insurance Services [Member] Non core benefits and insurance services. Goodwill Goodwill Interest rate swap, December 2026 expiration Interest Rate Swap, December 2026 Expiration [Member] Interest Rate Swap, December 2026 Expiration Income taxes payable Accrued Income Taxes, Current Adjustments to reconcile net income to net cash used in operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Subsequent Event Type [Axis] Subsequent Event Type [Axis] Change in net present value of contingencies Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Liability Change In Net Present Value Of Contingencies Fair value measurement with unobservable inputs reconciliation recurring basis liability change in net present value of contingencies.