Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2020	Oct. 29, 2020
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Trading Symbol	CBZ
Entity Registrant Name	CBIZ, Inc.
Entity Central Index Key	0000944148
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Shell Company	false
Title of 12(b) Security	Common Stock, $0.01 Par Value
Security Exchange Name	NYSE
Entity File Number	1-32961
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	22-2769024
Entity Address, Address Line One	6050 Oak Tree Boulevard
Entity Address, Address Line Two	South
Entity Address, Address Line Three	Suite 500
Entity Address, City or Town	Cleveland
Entity Address, State or Province	OH
Entity Address, Postal Zip Code	44131
City Area Code	216
Local Phone Number	447-9000
Document Transition Report	false
Document Quarterly Report	true
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		54,531,473