Loans and Allowance for Credit Losses - Troubled Debt Restructured Loans and Commitments (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Loans and Leases Receivable Disclosure [Abstract]
Accrual status	$ 13,495	$ 13,037	$ 20,276
Nonaccrual status	16,980	50,979	44,841
Total	30,475	64,016	65,117
Letters of credit	0	1,574	12,580
Unused lines of credit	452	0	42
Total	$ 452	$ 1,574	$ 12,622