NON-COVERED LOANS AND ALLOWANCE FOR LOAN LOSSES (Details 13) (USD $) In Thousands, unless otherwise specified	3 Months Ended			9 Months Ended				12 Months Ended
	Sep. 30, 2012		Sep. 30, 2011	Sep. 30, 2012		Sep. 30, 2011		Dec. 31, 2011
Financing Receivable Allowance for Credit Losses Roll Forward
Beginning balance	$ 226,627			$ 216,523		$ 234,633		$ 234,633
Provision for loan losses	18,500		22,000	52,100		75,006		95,006
Allowance for unfunded loan commitments and letters of credit	1,502			(2)				(1,048)
Charge-offs	(20,955)			(52,559)				(124,691)
Recoveries	3,840			13,452				12,623
Net charge-offs	(17,115)			(39,107)		(90,200)		(112,068)
Ending balance	229,514			229,514				216,523
Ending balance allocated to:
Loans individually evaluated for impairment	10,200			10,200				13,041
Loans collectively evaluated for impairment	219,314			219,314				203,482
Ending balance	229,514			229,514				216,523
Residential
Financing Receivable Allowance for Credit Losses Roll Forward
Beginning balance	49,985			52,180		49,491		49,491
Provision for loan losses	3,552			4,741				15,416
Charge-offs	(2,767)			(7,334)				(13,323)
Recoveries	71			1,254				596
Net charge-offs	(2,696)			(6,080)				(12,727)
Ending balance	50,841			50,841				52,180
Ending balance allocated to:
Loans individually evaluated for impairment	3,701			3,701				2,255
Loans collectively evaluated for impairment	47,140			47,140				49,925
Ending balance	50,841			50,841				52,180
Commercial Real Estate ("CRE")
Financing Receivable Allowance for Credit Losses Roll Forward
Beginning balance	72,076			66,457		117,752		117,752
Provision for loan losses	(744)			15,651				22,817
Charge-offs	(4,639)			(20,217)				(78,803)
Recoveries	2,058			6,860				4,691
Net charge-offs	(2,581)			(13,357)				(74,112)
Ending balance	68,751			68,751				66,457
Ending balance allocated to:
Loans individually evaluated for impairment	5,120			5,120				5,951
Loans collectively evaluated for impairment	63,631			63,631				60,506
Ending balance	68,751			68,751				66,457
Commercial and Industrial ("C&I")
Financing Receivable Allowance for Credit Losses Roll Forward
Beginning balance	92,615			87,020		59,737		59,737
Provision for loan losses	11,619			24,060				50,848
Charge-offs	(6,586)			(16,954)				(30,606)
Recoveries	1,708			5,230				7,041
Net charge-offs	(4,878)			(11,724)				(23,565)
Ending balance	99,356			99,356				87,020
Ending balance allocated to:
Loans individually evaluated for impairment	1,379			1,379				4,835
Loans collectively evaluated for impairment	97,977			97,977				82,185
Ending balance	99,356			99,356				87,020
Consumer
Financing Receivable Allowance for Credit Losses Roll Forward
Beginning balance	4,778			4,219		3,428		3,428
Provision for loan losses	396			1,941				2,455
Charge-offs	(488)			(1,579)				(1,959)
Recoveries	3			108				295
Net charge-offs	(485)			(1,471)				(1,664)
Ending balance	4,689			4,689				4,219
Ending balance allocated to:
Loans collectively evaluated for impairment	4,689			4,689				4,219
Ending balance	4,689			4,689				4,219
Covered Loans Subject to Allowance For Loan Losses
Financing Receivable Allowance for Credit Losses Roll Forward
Beginning balance	7,173	[1]		6,647	[1]	4,225	[1]	4,225	[1]
Provision for loan losses	5,179			5,705				2,422
Charge-offs	(6,475)	[1]		(6,475)	[1]
Net charge-offs	(6,475)	[1]		(6,475)	[1]
Ending balance	5,877	[1]		5,877	[1]			6,647	[1]
Ending balance allocated to:
Loans collectively evaluated for impairment	5,877	[1]		5,877	[1]			6,647	[1]
Ending balance	5,877	[1]		5,877	[1]			6,647	[1]
Unallocated
Financing Receivable Allowance for Credit Losses Roll Forward
Provision for loan losses	(1,502)			2				1,048
Allowance for unfunded loan commitments and letters of credit	$ 1,502			$ (2)				$ (1,048)

[1] This allowance is related to drawdowns on commitments that were in existence as of the acquisition dates of WFIB and UCB and, therefore, are covered under the shared-loss agreements with the FDIC. Allowance on these subsequent drawdowns is accounted for as part of the allowance for loan losses.