Allowance for Credit Losses - Summary of Provision for Credit Losses (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Banking And Thrift Interest [Abstract]
Provision for non-covered loans									$ 17,171	$ 25,640	$ 31,242
Provision for covered loans									(2,276)		21,510
Total provision for loan losses									14,895	25,640	52,752
Provision for unfunded letters of credit									1,200	(88)	583
Total provision for credit losses	$ 6,440	$ 5,334	$ 2,552	$ 1,769	$ 5,200	$ 7,250	$ 7,405	$ 5,697	$ 16,095	$ 25,552	$ 53,335