FDIC loss share (expense) income (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
F D I C Loss Share Expense Income [Line Items]
(Amortization) accretion of indemnification asset	$ (42,524)		$ (37,681)		$ (163,565)		$ (116,442)
Reversal of accelerated FDIC Indemnification Asset, Accretion of Discount	15,046		0		15,046		0
80% mirror accounting on credit impairment losses	9,863	[1]	13,946	[1]	35,325	[1]	53,329
80% mirror accounting on reimbursable expenses	15,545		25,641		39,375		45,555
80% mirror accounting on recoveries on covered assets, including rental income on OREOs, subject to reimbursement to the FDIC	(2,633)		(11,533)		(10,582)		(14,802)
80% mirror accounting on discount accretion on loans and unfunded commitments accounted for under ASC 310-20	0		(87)		0		(473)
Business Combination Contingent Consideration Arrangements Change In Amount Of Contingent Consideration Liability1	1,078		(5,322)		1,040		(12,573)
Other	(1,239)		170		(970)		519
Segment, Continuing Operations [Member]
F D I C Loss Share Expense Income [Line Items]
FDIC loss share (expense) income	$ (4,864)		$ (14,866)		$ (84,331)		$ (44,887)

[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.