Other Noninterest Income - Components of Other Noninterest Income (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Income Statement [Abstract]
Income from bank owned life insurance	$ 2,377	$ 2,656	$ 7,048	$ 8,764
Credit related fees	2,822	2,995	8,388	5,969
Income from derivatives	191	1,257	1,431	3,296
Net(loss) gain on sale of assets	(56)	801	1,409	1,277
Safety deposit box income	448	467	1,404	1,480
Other miscellaneous	1,950	1,940	7,091	6,453
Total other noninterest income	$ 7,732	$ 10,116	$ 26,771	$ 27,239