SUBSEQUENT EVENTS (Details) - Subsequent Event $ in Millions	Nov. 01, 2024 USD ($) installment shares
2024 Credit Facilities \| Line of credit
Subsequent Event [Line Items]
Line of credit facility, maximum borrowing capacity	$ 2,000.0
Annual amortization rate first two years	5.00%
Annual amortization rate third and fourth years	7.50%
Annual amortization rate, year five	10.00%
Covenant leverage ratio, maximum, tranche one	5.00
Covenant leverage ratio, maximum, tranche two	3.75
Covenant interest coverage ratio, minimum	3.00
Long-term line of credit	$ 1,465.5
2024 Credit Facilities \| Line of credit \| Fed Funds Effective Rate Overnight Index Swap Rate
Subsequent Event [Line Items]
Basis spread on variable rate	0.50%
2024 Credit Facilities \| Line of credit \| Secured Overnight Financing Rate (SOFR)
Subsequent Event [Line Items]
Basis spread on variable rate	1.00%
2024 Credit Facilities \| Line of credit \| SOFR Adjustment
Subsequent Event [Line Items]
Basis spread on variable rate	0.10%
2024 Credit Facilities \| Line of credit \| Adjusted Base Rate \| Minimum
Subsequent Event [Line Items]
Basis spread on variable rate	0.375%
2024 Credit Facilities \| Line of credit \| Adjusted Base Rate \| Maximum
Subsequent Event [Line Items]
Basis spread on variable rate	1.50%
2024 Credit Facilities \| Line of credit \| Adjusted Term Secured Overnight Financing Rate (SOFR) \| Minimum
Subsequent Event [Line Items]
Basis spread on variable rate	1.375%
2024 Credit Facilities \| Line of credit \| Adjusted Term Secured Overnight Financing Rate (SOFR) \| Maximum
Subsequent Event [Line Items]
Basis spread on variable rate	2.50%
2024 Credit Facilities \| Line of credit \| Secured Debt
Subsequent Event [Line Items]
Debt instrument, face amount	$ 1,400.0
2024 Credit Facilities \| Line of credit \| Revolving Credit Facility
Subsequent Event [Line Items]
Line of credit facility, maximum borrowing capacity	600.0
Incremental borrowing capacity	$ 465.0
Percent of EBITDA	100.00%
Net leverage ratio	3.50
Marcum
Subsequent Event [Line Items]
Cash paid	$ 637.6
Additional cash paid	$ 425.5
Common stock issued (in shares) \| shares	14,260,645
Number of shares deliverable, tranche one \| shares	713,032
Number of shares deliverable, tranche two \| shares	2,852,129
Number of shares deliverable, tranche three \| shares	10,695,484
Number of shares deliverable, tranche three, number of monthly installments \| installment	36

Business Acquisition, Equity Interest Issued Or Issuable, Number Of Shares Deliverable, Tranche One

No definition available.

Name:	cbz_BusinessAcquisitionEquityInterestIssuedOrIssuableNumberOfSharesDeliverableTrancheOne
Namespace Prefix:	cbz_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Business Acquisition, Equity Interest Issued Or Issuable, Number Of Shares Deliverable, Tranche Three

+ References

No definition available.

+ Details

Name:	cbz_BusinessAcquisitionEquityInterestIssuedOrIssuableNumberOfSharesDeliverableTrancheThree
Namespace Prefix:	cbz_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Business Acquisition, Equity Interest Issued Or Issuable, Number Of Shares Deliverable, Tranche Three, Number Of Monthly Installments

+ References

No definition available.

+ Details

Name:	cbz_BusinessAcquisitionEquityInterestIssuedOrIssuableNumberOfSharesDeliverableTrancheThreeNumberOfMonthlyInstallments
Namespace Prefix:	cbz_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Business Acquisition, Equity Interest Issued Or Issuable, Number Of Shares Deliverable, Tranche Two

+ References

No definition available.

+ Details

Name:	cbz_BusinessAcquisitionEquityInterestIssuedOrIssuableNumberOfSharesDeliverableTrancheTwo
Namespace Prefix:	cbz_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

Business Combination, Additional Cash Paid To Acquire Business

+ References

No definition available.

+ Details

Name:	cbz_BusinessCombinationAdditionalCashPaidToAcquireBusiness
Namespace Prefix:	cbz_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Debt Instrument, Annual Principal Amortization Payments Rate, Year Five

+ References

No definition available.

+ Details

Name:	cbz_DebtInstrumentAnnualPrincipalAmortizationPaymentsRateYearFive
Namespace Prefix:	cbz_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Annual Principal Amortization Payments Rate, Years One And Two

+ References

No definition available.

+ Details

Name:	cbz_DebtInstrumentAnnualPrincipalAmortizationPaymentsRateYearsOneAndTwo
Namespace Prefix:	cbz_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Annual Principal Amortization Payments Rate, Years Three And Four

+ References

No definition available.

+ Details

Name:	cbz_DebtInstrumentAnnualPrincipalAmortizationPaymentsRateYearsThreeAndFour
Namespace Prefix:	cbz_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Covenant, Interest Coverage Ratio, Minimum

+ References

No definition available.

+ Details

Name:	cbz_DebtInstrumentCovenantInterestCoverageRatioMinimum
Namespace Prefix:	cbz_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Covenant, Leverage Ratio, Maximum, Tranche One

+ References

No definition available.

+ Details

Name:	cbz_DebtInstrumentCovenantLeverageRatioMaximumTrancheOne
Namespace Prefix:	cbz_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Covenant, Leverage Ratio, Maximum, Tranche Two

+ References

No definition available.

+ Details

Name:	cbz_DebtInstrumentCovenantLeverageRatioMaximumTrancheTwo
Namespace Prefix:	cbz_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Debt Instrument, Covenant, Total Net Leverage Ratio, Maximum

+ References

No definition available.

+ Details

Name:	cbz_DebtInstrumentCovenantTotalNetLeverageRatioMaximum
Namespace Prefix:	cbz_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Line Of Credit Facility, Accordion Feature, Increase Limit

+ References

No definition available.

+ Details

Name:	cbz_LineOfCreditFacilityAccordionFeatureIncreaseLimit
Namespace Prefix:	cbz_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line Of Credit Facility, Accordion Feature, Percent Of EBITDA

+ References

No definition available.

+ Details

Name:	cbz_LineOfCreditFacilityAccordionFeaturePercentOfEBITDA
Namespace Prefix:	cbz_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of shares of equity interests issued or issuable to acquire entity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 805
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)(4)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479581/805-30-50-1

+ Details

Name:	us-gaap_BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 55
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482949/835-30-55-8

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481139/470-20-50-1B

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 69B
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481568/470-20-55-69B

Reference 4: http://www.xbrl.org/2003/role/exampleRef
-Topic 470
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 69C
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481568/470-20-55-69C

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482900/835-30-50-1

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 835
-SubTopic 30
-Name Accounting Standards Codification
-Section 45
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482925/835-30-45-2

+ Details

Name:	us-gaap_DebtInstrumentFaceAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-SubTopic 10
-Topic 210
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16)(a)(2))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478777/944-210-S99-1

+ Details

Name:	us-gaap_LineOfCredit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22)(b))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(19)(b))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 805
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479581/805-30-50-1

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-13

+ Details

Name:	us-gaap_PaymentsToAcquireBusinessesGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 830
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481674/830-30-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 855
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483399/855-10-50-2

+ Details

Name:	us-gaap_SubsequentEventLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=cbz_A2024CreditFacilitiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_LineOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_FederalFundsEffectiveSwapRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_SecuredOvernightFinancingRateSofrMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=cbz_SOFRAdjustmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=cbz_AdjustedBaseRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=cbz_AdjustedTermSecuredOvernightFinancingRateSOFRMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_SecuredDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=cbz_MarcumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: