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Goodwill and Identifiable Intangible Assets - Additional Information (Detail) - USD ($)
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Goodwill And Intangible Assets Disclosure [Abstract]      
Number of steps for goodwill impairment test Two    
Goodwill impairment loss $ 0    
Amortization expense of intangible assets acquired $ 94,900,000 $ 88,700,000 $ 118,900,000