Activity in the FDIC loss share indemnification asset (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013
Loss Share Indemnification Asset [Line Items]
Beginning Balance	$ 751,553		$ 1,379,342		$ 948,608		$ 1,399,098
Accretion of loss share indemnification asset, net	(42,524)		(37,681)		(163,565)		(116,442)
Reversal of accelerated FDIC Indemnification Asset, Accretion of Discount	15,046		0		15,046		0
Credit impairment losses to be covered under loss sharing agreements	9,863	[1]	13,946	[1]	35,325	[1]	53,329
F D I C Reimbursable Expenses	15,545		25,641		39,375		45,555
Decrease due to reciprocal accounting on the discount accreation for loans and unfunded commitments accounted for under ASC Subtopic 310-20	0		(87)		0		(473)
Payments (to) from the FDIC under the loss sharing agreements	(73,106)		(52,865)		(185,963)		(52,758)
Other adjustments attributable to FDIC loss sharing agreements	4,729		(3,585)		(7,720)		(3,598)
Ending Balance	$ 681,106		$ 1,324,711		$ 681,106		$ 1,324,711

[1] Reductions in expected cash flows for ASC 310-30 loans, which may impact the provision for loan losses, may consider reductions in both principal and interest cash flow expectations. The amount covered under the FDIC loss sharing agreements for interest not collected from borrowers is limited under the agreements (approximately 90 days); accordingly, these amounts are not subject fully to the 80% mirror accounting.