Goodwill and Other Intangible Assets - Schedule of Change in Loan Servicing Rights (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Goodwill [Roll Forward]
Balance at beginning of year	$ 16,681	$ 20,446	$ 26,068
Origination of loan servicing rights	8,479	1,696	1,065
Amortization expense	(4,792)	(5,461)	(6,687)
Balance at end of year	20,368	16,681	20,446
Balance at beginning of year	(289)	(592)	(504)
Impairment adjustment	(611)	303	(88)
Balance at end of year	(900)	(289)	(592)
Balance at end of year, net of valuation allowance	$ 19,468	$ 16,392	$ 19,854