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, 2013		Sep. 30, 2012	Sep. 30, 2013		Sep. 30, 2012		Dec. 31, 2012
Financing Receivable Allowance for Credit Losses Roll Forward
Beginning balance	$ 243,109			$ 234,535		$ 216,523		$ 216,523
Provision for loan losses	3,571		18,500	16,898		52,100		65,184
Allowance for unfunded loan commitments and letters of credit	(3,445)			(2,297)				1,563
Charge-offs	(2,399)			(12,651)				(64,912)
Recoveries	2,065			6,416				16,177
Net recoveries/(charge-offs)	(334)			(6,235)		(39,100)		(48,735)
Ending balance	242,901			242,901				234,535
Ending balance allocated to:
Loans individually evaluated for impairment	17,293			17,293				11,527
Loans collectively evaluated for impairment	223,271			223,271				223,008
Covered loans acquired with deteriorated credit quality	2,337	[1]		2,337	[1]
Ending balance	242,901			242,901				234,535
Residential
Financing Receivable Allowance for Credit Losses Roll Forward
Beginning balance	47,337			49,349		52,180		52,180
Provision for loan losses	3,402			1,180				3,255
Charge-offs	(432)			(1,293)				(7,700)
Recoveries	469			1,540				1,614
Net recoveries/(charge-offs)	37			247				(6,086)
Ending balance	50,776			50,776				49,349
Ending balance allocated to:
Loans individually evaluated for impairment	809			809				3,131
Loans collectively evaluated for impairment	49,967			49,967				46,218
Ending balance	50,776			50,776				49,349
Commercial Real Estate ("CRE")
Financing Receivable Allowance for Credit Losses Roll Forward
Beginning balance	72,830			69,856		66,457		66,457
Provision for loan losses	(3,169)			223				20,977
Charge-offs	(574)			(2,341)				(27,060)
Recoveries	270			1,619				9,482
Net recoveries/(charge-offs)	(304)			(722)				(17,578)
Ending balance	69,357			69,357				69,856
Ending balance allocated to:
Loans individually evaluated for impairment	6,045			6,045				5,561
Loans collectively evaluated for impairment	63,312			63,312				64,295
Ending balance	69,357			69,357				69,856
Commercial and Industrial ("C&I")
Financing Receivable Allowance for Credit Losses Roll Forward
Beginning balance	105,376			105,376		87,020		87,020
Provision for loan losses	(594)			3,347				35,204
Charge-offs	(1,387)			(6,464)				(21,818)
Recoveries	1,243			2,379				4,970
Net recoveries/(charge-offs)	(144)			(4,085)				(16,848)
Ending balance	104,638			104,638				105,376
Ending balance allocated to:
Loans individually evaluated for impairment	10,439			10,439				2,835
Loans collectively evaluated for impairment	94,199			94,199				102,541
Ending balance	104,638			104,638				105,376
Consumer
Financing Receivable Allowance for Credit Losses Roll Forward
Beginning balance	7,937			4,801		4,219		4,219
Provision for loan losses	1,451			5,003				2,295
Charge-offs	(6)			(1,217)				(1,824)
Recoveries	83			878				111
Net recoveries/(charge-offs)	77			(339)				(1,713)
Ending balance	9,465			9,465				4,801
Ending balance allocated to:
Loans collectively evaluated for impairment	9,465			9,465				4,801
Ending balance	9,465			9,465				4,801
Covered Loans under ASC 310-10 Subject to Allowance for Loan Losses
Financing Receivable Allowance for Credit Losses Roll Forward
Beginning balance	7,100	[2]		5,153	[2]	6,647	[2]	6,647	[2]
Provision for loan losses	(772)	[2]		2,511	[2]			5,016	[2]
Charge-offs				(1,336)	[2]			(6,510)	[2]
Net recoveries/(charge-offs)				(1,336)	[2]			(6,510)	[2]
Ending balance	6,328	[2]		6,328	[2]			5,153	[2]
Ending balance allocated to:
Loans collectively evaluated for impairment	6,328	[2]		6,328	[2]			5,153	[2]
Ending balance	6,328	[2]		6,328	[2]			5,153	[2]
Covered Loans under ASC 310-30 Subject to Allowance for Loan Losses
Financing Receivable Allowance for Credit Losses Roll Forward
Beginning balance	2,529
Provision for loan losses	(192)			2,337
Ending balance	2,337			2,337
Ending balance allocated to:
Covered loans acquired with deteriorated credit quality	2,337	[1]		2,337	[1]
Ending balance	2,337			2,337
Unallocated
Financing Receivable Allowance for Credit Losses Roll Forward
Provision for loan losses	3,445			2,297				(1,563)
Allowance for unfunded loan commitments and letters of credit	$ (3,445)			$ (2,297)				$ 1,563

[1] The Company has elected to account for covered loans acquired in the FDIC-assisted acquisitions under ASC 310-30, excluding any additional advances subsequent to acquisition date.

[2] 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.