Foreclosed Assets - Summary of Activity in Balance of Foreclosed Assets (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($) Assets	Dec. 31, 2015 USD ($) Assets	Dec. 31, 2014 USD ($)
Schedule Of Foreclosed Assets Activity [Line Items]
Beginning balance, net	$ 5,369	$ 4,894
Additions/transfers from loans	2,505	5,435
Dispositions/sales	(3,748)	(4,458)
Valuation adjustments	(140)	(502)
Ending balance, net	3,986	5,369	$ 4,894
Ending valuation allowance	$ (314)	$ (572)
Ending number of foreclosed assets | Assets	15	26
Proceeds from sale of foreclosed assets	$ 4,010	$ 5,449
Gain on sale of foreclosed assets	262	991	2,153
Noncovered [Member]
Schedule Of Foreclosed Assets Activity [Line Items]
Beginning balance, net	5,369	4,449
Additions/transfers from loans	2,282	5,880
Dispositions/sales	(3,748)	(4,458)
Valuation adjustments	(140)	(502)
Ending balance, net	3,763	5,369	4,449
Ending valuation allowance	$ (314)	$ (572)
Ending number of foreclosed assets | Assets	14	26
Proceeds from sale of foreclosed assets	$ 4,010	$ 5,449
Gain on sale of foreclosed assets	262	991
Covered [Member]
Schedule Of Foreclosed Assets Activity [Line Items]
Beginning balance, net		445
Additions/transfers from loans	223	$ (445)
Ending balance, net	$ 223		$ 445
Ending number of foreclosed assets | Assets	1