Annual report pursuant to Section 13 and 15(d)

Retirement Plan - Additional Information (Detail)

v2.4.1.9
Retirement Plan - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Compensation and Retirement Disclosure [Abstract]    
Retirement plan contribution by company $ 2.6us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount $ 2.7us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount