Loans and Allowance for Loan Losses - Schedule of Activity in Loss Share Receivable (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Receivables [Abstract]
Balance, January 1	$ 177,844	$ 231,085
Discount accretion		5,000
Charge-offs, write-downs and other losses	1,668	35,844
External expenses qualifying under loss share agreement	6,307	5,072
Payments received from the FDIC	(33,919)	(62,059)
Ending balance	$ 151,900	$ 214,942