NON-COVERED LOANS AND ALLOWANCE FOR LOAN LOSSES (Details 3) (USD $)	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Credit Risk and Concentrations
Percentage of non-covered commercial real estate loans and non-covered residential loans secured by real properties located in California	89.00%
Loans receivable, excluding covered loans, gross	$ 11,958,873,000	$ 10,288,426,000
Purchased Loans
Loans acquired during the period	591,200,000
Carrying amount of loans acquired	564,800,000
Percentage of purchased loans classified as student loans	94.00%
Loans Held for Sale
Total loans held for sale	174,317,000	278,603,000
Percentage of loans held for sale that were originally classified as student loans	96.00%
Proceeds from the sales of Loans held for sale, including loans reclassified to loans held for sale	351,900,000	652,700,000	409,500,000
Net gain from sale of loans held for sale during the period	14,600,000	14,500,000	18,500,000
Loans receivable reclassified to loans held for sale	144,131,000	644,915,000	563,974,000
Residential
Credit Risk and Concentrations
Loans receivable, excluding covered loans, gross	3,088,031,000	2,729,803,000
Commercial Real Estate ("CRE")
Credit Risk and Concentrations
Loans receivable, excluding covered loans, gross	$ 3,894,695,000	$ 3,832,365,000

The carrying amount of loans acquired during the reporting period.

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Loans acquired during the reporting period.

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The percentage of non-covered commercial real estate loans and non-covered residential loans secured by real properties located in California.

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No definition available.

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Reflects the gross carrying amount of all categories of non-covered loans held in portfolio.

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Percentage of loans held for sale as of the reporting date that were originally classified as student loans.

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No definition available.

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Represents the percentage of purchased loans classified as student loans.

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The gains (losses) included in earnings that represent the difference between the sale price and the carrying value of loans and leases that were sold during the reporting period. This element refers to the gain (loss) and not to the cash proceeds of the sales. This element is a noncash adjustment to net income when calculating net cash generated by operating activities using the indirect method.

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The aggregate carrying amount of loans receivable that will be sold to other entities. Includes mortgage and all other loans (collectively, loans) not classified as held for investment. Such loans are stated at the lower of cost or market, or elected fair value. Mortgage loans exclude mortgage-backed securities which are considered a debt security (other loan).

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The cash inflow resulting from the sale of loans classified as held-for-sale, including proceeds from loans sold through mortgage securitization.

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Value of loans and leases held in the entity's portfolio transferred to loans and leases held-for-sale in noncash transactions.

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