Foreclosed Assets - Summary of Activity in Balance of Foreclosed Assets (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014 Assets	Sep. 30, 2013 Assets
Schedule Of Foreclosed Assets Activity [Line Items]
Beginning balance, net	$ 6,262	$ 7,498
Additions/transfers from loans	4,936	8,035
Dispositions/sales	(5,965)	(10,773)
Valuation adjustments	(137)	(620)
Ending balance, net	5,096	4,140
Ending valuation allowance	(181)	(927)
Ending number of foreclosed assets	25	31
Proceeds from sale of foreclosed assets	7,818	12,252
Gain on sale of foreclosed assets	1,853	1,479
Noncovered [Member]
Schedule Of Foreclosed Assets Activity [Line Items]
Beginning balance, net	5,588	5,957
Additions/transfers from loans	4,936	7,542
Dispositions/sales	(5,823)	(10,004)
Valuation adjustments	(125)	(539)
Ending balance, net	4,576	2,956
Ending valuation allowance	(169)	(587)
Ending number of foreclosed assets	23	26
Proceeds from sale of foreclosed assets	7,650	11,383
Gain on sale of foreclosed assets	1,827	1,379
Covered [Member]
Schedule Of Foreclosed Assets Activity [Line Items]
Beginning balance, net	674	1,541
Additions/transfers from loans		493
Dispositions/sales	(142)	(769)
Valuation adjustments	(12)	(81)
Ending balance, net	520	1,184
Ending valuation allowance	(12)	(340)
Ending number of foreclosed assets	2	5
Proceeds from sale of foreclosed assets	168	869
Gain on sale of foreclosed assets	$ 26	$ 100