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Financial Instruments - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified
 12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Derivative Instruments and Hedging Activities Disclosure [Abstract]    
Corporate and municipal bonds $ 36.4cbz_CorporateAndMunicipalBondsParValue $ 29.0cbz_CorporateAndMunicipalBondsParValue
Maturity dates of bonds, start date 2015-01  
Maturity dates of bonds, end date 2019-11