Goodwill and Other Intangible Assets - Additional Information (Detail) - USD ($)
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Goodwill and Intangible Assets Disclosure [Abstract]      
Goodwill $ 74,565,000 $ 11,265,000  
Impairment of goodwill 0 0 $ 0
Amortization expense $ 1,300,000 $ 900,000 $ 900,000