Loans - Change in Accretable Yield for PCI (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Change in accretable yield:
Balance at beginning of period	$ 11,775	$ 12,947	$ 13,255	$ 14,159
Accretion to interest income	(961)	(1,510)	(3,068)	(4,440)
Reclassification (to) from nonaccretable difference	(160)	1,439	467	3,157
Balance at end of period	$ 10,654	$ 12,876	$ 10,654	$ 12,876