Goodwill and Intangibles - Summary of Change in Carrying Amount of Goodwill (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill (Gross), beginning balance	$ 160,516	$ 123,397
Business combinations	16,918	37,104
Other	(344)	15
Goodwill (Gross), ending balance	177,090	160,516
Accumulated Impairment Losses, beginning balance	(70,004)	(70,004)
Accumulated Impairment Losses, ending balance	(70,004)	(70,004)
Goodwill (Net), beginning balance	90,512	53,393
Business combinations	16,918	37,104
Other	(344)	15
Goodwill (Net), ending balance	$ 107,086	$ 90,512