Other Noninterest Income - Components of Other Noninterest Income (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Noninterest Income [Abstract]
Income from bank-owned life insurance	$ 2,671	$ 2,357	$ 5,337	$ 4,671
Credit related fees	2,611	2,834	5,068	5,566
Income from derivatives	1,464	481	1,412	1,240
Net (loss) gain on sale of assets	(62)	(217)	(55)	1,465
Safety deposit box income	429	443	915	956
Other miscellaneous	2,412	2,714	5,092	5,141
Total other noninterest income	$ 9,525	$ 8,612	$ 17,769	$ 19,039