MORTGAGE SERVICING RIGHTS (Details) (USD $)	3 Months Ended	9 Months Ended	12 Months Ended
Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010
Data and assumptions used in fair value calculation [Abstract]
Unpaid principal balance	$ 4,143,880,000	$ 3,690,125,000	$ 4,143,880,000	$ 3,690,125,000	$ 3,870,872,000
Weighted-average prepayment speed (CPR)			22.70%	23.20%	15.60%
Discount rate (annual percentage) (in hundredths)			10.30%	10.30%	10.30%
Weighted-average coupon interest rate (percentage) (in hundredths)			5.10%	5.40%	5.20%
Weighted-average remaining maturity (in months)			314.0	318.0	315.0
Weighted-average servicing fee basis points (in hundredths)			0.281%	0.286%	0.284%
Contractually specified servicing fees, late fees, and ancillary fees [Abstract]
Contractual servicing fees	2,900,000	2,600,000	8,600,000	7,700,000
Late and other ancillary fees	334,000	358,000	966,000	1,000,000
Closed End Loans for One-to-Four Family Residences, Secured by First Liens [Member]
Activity in mortgage servicing asset [Roll Forward]
Fair value as of beginning of period			38,642,000	35,560,000	35,560,000
Additions:
Origination of servicing assets			7,938,000	9,173,000
Changes in fair value:
Due to payoffs/paydowns			(4,435,000)	(4,900,000)
Due to change in valuation inputs or assumptions used in the valuation model			(12,975,000)	(12,924,000)
Other changes in fair value			(11,000)	(8,000)
Fair value as of end of period	$ 29,159,000	$ 26,901,000	$ 29,159,000	$ 26,901,000

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All amounts that are due to the servicer of a financial asset as a result of the debt holder not meeting the monthly payment terms, and all other amounts due to the servicer, excluding contractually specified servicing fees and late fees.

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The weighted-average coupon interest rate, which may be one of the factors applied in estimating the fair value of servicing assets.

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The weighted-average servicing fee, which may be one of the factors applied in estimating the fair value of servicing assets.

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All amounts that, per contract, are due to the servicer in exchange for servicing the financial asset and would no longer be received by a servicer if the beneficial owners of the serviced assets (or their trustees or agents) were to exercise their actual or potential authority under the contract to shift the servicing to another servicer. Depending on the servicing contract, those fees may include some or all of the difference between the interest rate collected on the asset being serviced and the rate to be paid to the beneficial owners of the asset.

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The increase during the reporting period in the cumulative value of servicing rights. This increase is the result of new servicing rights that are created when mortgages are sold or transferred.

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Amortized carrying amount (balance) as of the balance sheet date of an asset representing net future revenues from contractually specified servicing fees, late charges, and other ancillary revenues, in excess of future costs related to servicing arrangements.

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Fair value as of the balance sheet date of an asset representing net future revenues from contractually specified servicing fees, late charges, and other ancillary revenues, in excess of future costs related to servicing arrangements.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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The net Increase or Decrease in fair value as a result of changes in the inputs, assumptions, or model used to calculate the fair value of servicing assets.

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The net Increase or Decrease in fair value as a result of other changes that are not additions, disposals, or a result of change in the inputs, assumptions, or model used to calculate the fair value of servicing assets.

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Other net Increase or Decrease in the balance in servicing assets subsequently measured at fair value. This element is for changes other than additions, disposals, changes in fair value resulting from changes in valuation inputs or changes in assumptions, or other changes in fair value.

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The discount rate used to estimate the fair value of servicing assets and servicing liabilities.

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The estimated speed of prepayments of principal on financial assets which may be one of the factors applied in estimating the fair value of servicing assets and servicing liabilities.

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The weighted average life of financial assets and financial liabilities which is used to estimate fair value of servicing assets and servicing liabilities.

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