Allowance for Credit Losses - Summary of Allowance for Credit Losses (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Receivables [Abstract]
Allowance for non-covered loans	$ 106,547	$ 120,708
Allowance for covered loans	7,070	9,492
Total allowance for loan losses	113,617	130,200	133,802
Allowance for unfunded letters of credit	3,495	2,295
Total allowance for credit losses	$ 117,112	$ 132,495