COVERED ASSETS AND FDIC INDEMNIFICATION ASSET (Details 4) (USD $)	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010
FDIC indemnification asset activity
Balance at beginning of period	$ 785,035,000		$ 1,091,814,000
Addition due to WFIB acquisition			41,131,000
(Amortization) Accretion	(59,929,000)		14,678,000
Reductions	(210,365,000)	[1],[2]	(355,490,000)	[1],[2]
Estimate of FDIC repayment	(3,606,000)	[3]	(7,098,000)	[3]
Balance at end of period	511,135,000		785,035,000
Amount of chargeoffs recoverable from the FDIC	126,400,000		227,600,000
FDIC Receivable
FDIC loss sharing receivable	$ 76,600,000		$ 62,600,000
Percentage of eligible losses for which the FDIC is obligated to reimburse the Company	80.00%
Percentage of reimbursable expenses that are loan-related and OREO expenses that are recorded as non-interest expense	100.00%
Percentage of any reimbursable expense recorded as noninterest income	80.00%
Percentage of actual expense paid by the Company	20.00%

[1] For the twelve months ended December 31, 2011, the reduction amount of $210.4 million also includes charge-offs, of which $126.4 million of these charge-offs are recoverable from the FDIC and recorded in other assets until reimbursement is received. For the twelve months ended December 31, 2010, the reduction amount of $355.5 million also includes charge-offs, of which $227.6 million are recoverable from the FDIC and recorded in other assets. Reductions relate to higher cash flows received from principal amortization, partial prepayments, loan payoffs and loan sales and the reduction of the credit discount.

[2] Reductions relate to higher cash flows received from principal amortization, partial prepayments, loan payoffs and loan sales.

[3] This represents the change in the calculated estimate the Company will be required to pay the FDIC at the end of the FDIC loss share agreements, due to lower thresholds of losses.