Goodwill and Other Intangible Assets - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($) event	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill acquired	$ 115,944	$ 0
Acquisition of core deposits	6,100
Acquisition of wealth management relationships	100
Acquisition of insurance contract relationships	400
Finite-lived Intangible Assets Acquired	$ 5,713	0
Number of triggering events | event	0
Amortization expense on finite-lived intangible assets	$ 1,818	$ 1,129	$ 1,591