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Goodwill and Intangible Assets - Additional Information (Detail) - USD ($)
3 Months Ended 9 Months Ended
Sep. 30, 2017
Sep. 30, 2016
Sep. 30, 2017
Sep. 30, 2016
Goodwill And Intangible Assets Disclosure [Abstract]        
Amortization expense of finite life intangible assets $ 2,900,000 $ 3,500,000 $ 8,666,000 $ 11,123,000
Goodwill, finite life or indefinite life intangible asset charges $ 0   $ 0