Summary of Significant Accounting Policies (Policies)	9 Months Ended
Sep. 30, 2021
Accounting Policies [Abstract]
Description of Business	Description of Business: CBIZ, Inc. is a diversified services company which, acting through its subsidiaries, has been providing professional business services since 1996, primarily to small and medium-sized businesses, as well as individuals, governmental entities, and not-for-profit enterprises throughout the United States and parts of Canada. CBIZ, Inc. manages and reports its operations along three practice groups: Financial Services, Benefits and Insurance Services and National Practices. A further description of products and services offered by each of the practice groups is provided in Note 12, Segment Disclosures, to the accompanying unaudited condensed consolidated financial statements.
Basis of Consolidation	Basis of Consolidation: The accompanying unaudited condensed consolidated financial statements include the operations of CBIZ, Inc. and all of its wholly-owned subsidiaries (“CBIZ”, the “Company”, “we”, “us”, or “our”), after elimination of all intercompany balances and transactions. These unaudited condensed consolidated financial statements do not reflect the operations or accounts of variable interest entities as the impact is not material to the financial condition, results of operations or cash flows of CBIZ.
Unaudited Interim Financial Statements	Unaudited Interim Financial Statements: The condensed consolidated financial statements have been prepared in accordance with GAAP and applicable rules and regulations of the SEC regarding interim financial reporting. Certain information and note disclosures normally included in the financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. As such, the information included in this quarterly report on Form 10-Q should be read in conjunction with the consolidated financial statements and accompanying notes included in our Annual Report on Form 10-K for the fiscal year ended December 31, 2020. In the opinion of CBIZ management, the accompanying unaudited condensed consolidated financial statements reflect all normal recurring adjustments necessary to present fairly the financial condition, results of operations, and cash flows for the interim periods presented, but are not necessarily indicative of the results of operations to be anticipated for the full year ending December 31, 2021.
Use of Estimates	Use of Estimates: The preparation of condensed consolidated financial statements in conformity with GAAP requires us to make estimates and assumptions that affect the amounts reported and disclosed in the financial statements and the accompanying notes. Changes in circumstances could cause actual results to differ materially from these estimates.
Changes in Accounting Policies	Changes in Accounting Policies: We have consistently applied the accounting policies for the periods presented as described in Note 1, Basis of Presentation and Significant Accounting Policies, to the consolidated financial statements contained in our Annual Report on Form 10-K for the fiscal year ended December 31, 2020.
New Accounting Pronouncements	NEW ACCOUNTING PRONOUNCEMENTS The FASB ASC is the sole source of authoritative GAAP other than the SEC issued rules and regulations that apply only to SEC registrants. The FASB issues an accounting standard to communicate changes to the FASB codification. We assess and review the impact of all accounting standards. Any accounting standards not listed below were reviewed and determined to be either not applicable or are not expected to have a material impact on the consolidated financial statements of the Company. Accounting Standards Issued But Not Yet Adopted Reference Rate Reform: In March 2020, the FASB issued ASU No. 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting, which provides optional expedients and exceptions for applying GAAP to contracts, hedging relationships, and other transactions affected by reference rate reform if certain criteria are met. The amendments in this ASU are effective for all entities through December 31, 2022. We are currently evaluating the effect of this new standard on our consolidated financial statements and have not adopted any of the transition relief available under the new guidance as of September 30, 2021. Subsequently, in January 2021, the FASB issued ASU No. 2021-01, Reference Rate Reform (Topic 848): Scope, which provides optional temporary guidance for entities transitioning away from the LIBOR and other interbank offered rates to new reference rates so that derivatives affected by the discounting transition are explicitly eligible for certain optional expedients and exceptions within Topic 848. This ASU clarifies that the derivative instruments affected by the discounting transition are explicitly eligible for certain optional expedients and exceptions provided in Topic 848. ASU 2021-01 is effective immediately for all entities. Entities may elect to apply the amendments on a full retrospective basis as of any date from the beginning of an interim period that includes or is subsequent to March 12, 2020, or on a prospective basis to new modifications from any date within an interim period that includes or is subsequent to the date of the issuance of a final update, up to the date that financial statements are available to be issued. The amendments provided in this ASU do not apply to contract modifications made, as well as new hedging relationships entered into, after December 31, 2022, and to existing hedging relationships evaluated for effectiveness for periods after December 31, 2022, except for certain hedging relationships existing as of December 31, 2022, that apply certain optional expedients in which the accounting effects are recorded through the end of the hedging relationship. We are currently evaluating the effect of this new standard on our consolidated financial statements and have not adopted any of the transition relief available under the new guidance as of September 30, 2021.

Summary of Significant Accounting Policies (Policies)

9 Months Ended

Sep. 30, 2021

Description of Business: CBIZ, Inc. is a diversified services company which, acting through its subsidiaries, has been providing professional business services since 1996, primarily to small and medium-sized businesses, as well as individuals, governmental entities, and not-for-profit enterprises throughout the United States and parts of Canada. CBIZ, Inc. manages and reports its operations along three practice groups: Financial Services, Benefits and Insurance Services and National Practices. A further description of products and services offered by each of the practice groups is provided in Note 12, Segment Disclosures, to the accompanying unaudited condensed consolidated financial statements.

Basis of Consolidation

Basis of Consolidation: The accompanying unaudited condensed consolidated financial statements include the operations of CBIZ, Inc. and all of its wholly-owned subsidiaries (“CBIZ”, the “Company”, “we”, “us”, or “our”), after elimination of all intercompany balances and transactions. These unaudited condensed consolidated financial statements do not reflect the operations or accounts of variable interest entities as the impact is not material to the financial condition, results of operations or cash flows of CBIZ.

Unaudited Interim Financial Statements

Unaudited Interim Financial Statements: The condensed consolidated financial statements have been prepared in accordance with GAAP and applicable rules and regulations of the SEC regarding interim financial reporting. Certain information and note disclosures normally included in the financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations. As such, the information included in this quarterly report on Form 10-Q should be read in conjunction with the consolidated financial statements and accompanying notes included in our Annual Report on Form 10-K for the fiscal year ended December 31, 2020.

In the opinion of CBIZ management, the accompanying unaudited condensed consolidated financial statements reflect all normal recurring adjustments necessary to present fairly the financial condition, results of operations, and cash flows for the interim periods presented, but are not necessarily indicative of the results of operations to be anticipated for the full year ending December 31, 2021.

Use of Estimates

Use of Estimates: The preparation of condensed consolidated financial statements in conformity with GAAP requires us to make estimates and assumptions that affect the amounts reported and disclosed in the financial statements and the accompanying notes. Changes in circumstances could cause actual results to differ materially from these estimates.

Changes in Accounting Policies

Changes in Accounting Policies: We have consistently applied the accounting policies for the periods presented as described in Note 1, Basis of Presentation and Significant Accounting Policies, to the consolidated financial statements contained in our Annual Report on Form 10-K for the fiscal year ended December 31, 2020.

New Accounting Pronouncements

NEW ACCOUNTING PRONOUNCEMENTS

The FASB ASC is the sole source of authoritative GAAP other than the SEC issued rules and regulations that apply only to SEC registrants. The FASB issues an accounting standard to communicate changes to the FASB codification. We assess and review the impact of all accounting standards. Any accounting standards not listed below were reviewed and determined to be either not applicable or are not expected to have a material impact on the consolidated financial statements of the Company.

Accounting Standards Issued But Not Yet Adopted

Reference Rate Reform: In March 2020, the FASB issued ASU No. 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting, which provides optional expedients and exceptions for applying GAAP to contracts, hedging relationships, and other transactions affected by reference rate reform if certain criteria are met. The amendments in this ASU are effective for all entities through December 31, 2022. We are currently evaluating the effect of this new standard on our consolidated financial statements and have not adopted any of the transition relief available under the new guidance as of September 30, 2021.

Subsequently, in January 2021, the FASB issued ASU No. 2021-01, Reference Rate Reform (Topic 848): Scope, which provides optional temporary guidance for entities transitioning away from the LIBOR and other interbank offered rates to new reference rates so that derivatives affected by the discounting transition are explicitly eligible for certain optional expedients and exceptions within Topic 848. This ASU clarifies that the derivative instruments affected by the discounting transition are explicitly eligible for certain optional expedients and exceptions provided in Topic 848. ASU 2021-01 is effective immediately for all entities. Entities may elect to apply the amendments on a full retrospective basis as of any date from the beginning of an interim period that includes or is subsequent to March 12, 2020, or on a prospective basis to new modifications from any date within an interim period that includes or is subsequent to the date of the issuance of a final update, up to the date that financial statements are available to be issued. The amendments provided in this ASU do not apply to contract modifications made, as well as new hedging relationships entered into, after December 31, 2022, and to existing hedging relationships evaluated for effectiveness for periods after December 31, 2022, except for certain hedging relationships existing as of December 31, 2022, that apply certain optional expedients in which the accounting effects are recorded through the end of the hedging relationship. We are currently evaluating the effect of this new standard on our consolidated financial statements and have not adopted any of the transition relief available under the new guidance as of September 30, 2021.