Loans Receivable - Schedule of FDIC Loss Share Receivable (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Loans Receivable [Line Items]
Balance	$ 423,069
Accretion (Amortization) of FDIC loss share receivable	(27,702)	(27,927)
Impairment	(31,813)
Balance	284,471
FDIC Loss Share Receivable [Member]
Loans Receivable [Line Items]
Balance	423,069	591,844
Change due to (reversal of) credit loss provision recorded on FDIC covered loans	(45,414)	684
Accretion (Amortization) of FDIC loss share receivable	(27,702)	(27,927)
Submission of reimbursable losses to the FDIC	(30,491)	(28,418)
Impairment	(31,813)
Changes due to a change in cash flow assumptions on OREO	(3,178)	1,265
Balance	$ 284,471	$ 537,448