XML 120 R88.htm IDEA: XBRL DOCUMENT v2.4.1.9
Employee Benefits - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified
 12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Compensation and Retirement Disclosure [Abstract]      
Maximum percentage of a participant's eligible compensation that a participating may elect to contribute, on a tax-deferred annually to the plan (as a percent) 50.00% 80.00%cbz_DefinedContributionPlanMaximumEmployeeContributionPercentage    
Percentage of matching contribution made by company, of first 6% of participating employees contributions (as a percent) 50.00%us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent    
Percentage of participating employees contribution, matched 100% (as a percent) 6.00%cbz_DefinedContributionPlanPercentageOfBaseCompensation    
Employer contribution $ 8.5us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount $ 7.9us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount $ 7.2us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount
Deferred gains or (losses) of investment $ 3.7cbz_DeferredCompensationPlanGainLossOnInvestments $ 8.2cbz_DeferredCompensationPlanGainLossOnInvestments $ 4.3cbz_DeferredCompensationPlanGainLossOnInvestments