NON-COVERED LOANS AND ALLOWANCE FOR LOAN LOSSES (Details 13) (USD $) In Thousands, unless otherwise specified	3 Months Ended												12 Months Ended
	Dec. 31, 2013		Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013		Dec. 31, 2012		Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012		Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Financing Receivable Allowance for Credit Losses Roll Forward
Beginning balance					$ 234,535						$ 216,523		$ 234,535		$ 216,523
Provision for loan losses													22,364		65,184		95,006
Allowance for unfunded loan commitments and letters of credit													(2,157)		1,563
Charge-offs	(6,286)		(4,535)	(8,277)	762		(13,773)		(13,321)	(16,595)	(16,479)		(17,780)		(64,912)
Recoveries													12,713		16,177
Net (charge-offs)/recoveries													(5,067)		(48,735)
Ending balance	249,675						234,535						249,675		234,535		216,523
Ending balance allocated to:
Loans individually evaluated for impairment	24,143						11,527						24,143		11,527
Loans collectively evaluated for impairment	223,263						223,008						223,263		223,008
Covered loans acquired with deteriorated credit quality	2,269	[1]											2,269	[1]
Ending balance	249,675						234,535						249,675		234,535		216,523
Residential
Financing Receivable Allowance for Credit Losses Roll Forward
Beginning balance					49,349						52,180		49,349		52,180
Provision for loan losses													1,918		3,255
Charge-offs													(3,197)		(7,700)
Recoveries													2,647		1,614
Net (charge-offs)/recoveries													(550)		(6,086)
Ending balance	50,717						49,349						50,717		49,349
Ending balance allocated to:
Loans individually evaluated for impairment	1,546						3,131						1,546		3,131
Loans collectively evaluated for impairment	49,171						46,218						49,171		46,218
Ending balance	50,717						49,349						50,717		49,349
Commercial Real Estate ("CRE")
Financing Receivable Allowance for Credit Losses Roll Forward
Beginning balance					69,856						66,457		69,856		66,457
Provision for loan losses													(6,615)		20,977
Charge-offs													(3,357)		(27,060)
Recoveries													4,793		9,482
Net (charge-offs)/recoveries													1,436		(17,578)
Ending balance	64,677						69,856						64,677		69,856
Ending balance allocated to:
Loans individually evaluated for impairment	8,058						5,561						8,058		5,561
Loans collectively evaluated for impairment	56,619						64,295						56,619		64,295
Ending balance	64,677						69,856						64,677		69,856
Commercial and Industrial ("C&I")
Financing Receivable Allowance for Credit Losses Roll Forward
Beginning balance					105,376						87,020		105,376		87,020
Provision for loan losses													12,821		35,204
Charge-offs													(7,405)		(21,818)
Recoveries													4,392		4,970
Net (charge-offs)/recoveries													(3,013)		(16,848)
Ending balance	115,184						105,376						115,184		105,376
Ending balance allocated to:
Loans individually evaluated for impairment	14,539						2,835						14,539		2,835
Loans collectively evaluated for impairment	100,645						102,541						100,645		102,541
Ending balance	115,184						105,376						115,184		105,376
Consumer
Financing Receivable Allowance for Credit Losses Roll Forward
Beginning balance					4,801						4,219		4,801		4,219
Provision for loan losses													8,055		2,295
Charge-offs													(2,385)		(1,824)
Recoveries													881		111
Net (charge-offs)/recoveries													(1,504)		(1,713)
Ending balance	11,352						4,801						11,352		4,801
Ending balance allocated to:
Loans collectively evaluated for impairment	11,352						4,801						11,352		4,801
Ending balance	11,352						4,801						11,352		4,801
Covered Loans under ASC 310-10 Subject to Allowance for Loan Losses
Financing Receivable Allowance for Credit Losses Roll Forward
Beginning balance					5,153	[2]					6,647	[2]	5,153	[2]	6,647	[2]
Provision for loan losses													1,759	[2]	5,016	[2]
Charge-offs													(1,436)	[2]	(6,510)	[2]
Net (charge-offs)/recoveries													(1,436)	[2]	(6,510)	[2]
Ending balance	5,476	[2]					5,153	[2]					5,476	[2]	5,153	[2]
Ending balance allocated to:
Loans collectively evaluated for impairment	5,476	[2]					5,153	[2]					5,476	[2]	5,153	[2]
Ending balance	5,476	[2]					5,153	[2]					5,476	[2]	5,153	[2]
Covered Loans under ASC 310-30 Subject to Allowance for Loan Losses
Financing Receivable Allowance for Credit Losses Roll Forward
Provision for loan losses													2,269
Ending balance	2,269												2,269
Ending balance allocated to:
Covered loans acquired with deteriorated credit quality	2,269	[1]											2,269	[1]
Ending balance	2,269												2,269
Unallocated
Financing Receivable Allowance for Credit Losses Roll Forward
Provision for loan losses													2,157		(1,563)
Allowance for unfunded loan commitments and letters of credit													$ (2,157)		$ 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.