Basis of Presentation and Accounting Policies (Detail) - Effect of a correction on the Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Accretion and amortization of purchase accounting adjustments	$ (6,278)	$ (1,246)
Loans originated for sale	(156,401)	(162,244)
Proceeds from loans held for sale	181,983	162,281
Gain on sale of premises and equipment	(288)	(38)
FDIC reimbursement of covered assets	20,738	4,760
Other	(4,224)	(960)
Net cash provided by operating activities	48,240	15,939
Decrease in loans, net	14,170	12,099
Proceeds from sale of other real estate owned	5,374	6,391
Increase in premises and equipment, net	376	(1,581)
Net cash used in investing activities	(40,326)	(24,772)
Scenario, Previously Reported [Member]
Accretion and amortization of purchase accounting adjustments		(5,292)
Loans originated for sale		(162,090)
Proceeds from loans held for sale		161,213
Gain on sale of premises and equipment		0
FDIC reimbursement of covered assets		5,368
Other		294
Net cash provided by operating activities		12,879
Decrease in loans, net		14,969
Proceeds from sale of other real estate owned		6,638
Increase in premises and equipment, net		(1,638)
Net cash used in investing activities		(21,712)
Scenario, Adjustment [Member]
Accretion and amortization of purchase accounting adjustments		4,046
Loans originated for sale		(154)
Proceeds from loans held for sale		1,068
Gain on sale of premises and equipment		(38)
FDIC reimbursement of covered assets		(608)
Other		(1,254)
Net cash provided by operating activities		3,060
Decrease in loans, net		(2,870)
Proceeds from sale of other real estate owned		(247)
Increase in premises and equipment, net		57
Net cash used in investing activities		$ (3,060)