Discontinued Operations and Divestitures - Additional Information (Detail)	9 Months Ended
Sep. 30, 2017 Business Office	Sep. 30, 2016 Business Office
Discontinued Operations And Disposal Groups [Abstract]
Number of business divestiture \| Office	0	0
Number of businesses sold \| Business	0	0

Discontinued operations number of operations sold.

No definition available.

Name:	cbz_DiscontinuedOperationsNumberOfOperationsSold
Namespace Prefix:	cbz_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration