Fair Value Measurements - Additional Information (Detail) - USD ($)	9 Months Ended
Sep. 30, 2018	Sep. 30, 2017
Fair Value Disclosures [Abstract]
Fair Value Measurements, Inter-transfers between Levels	$ 0	$ 0

Fair value measurements inter transfers between levels.

No definition available.

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