NON COVERED LOANS AND ALLOWANCE FOR LOAN LOSSES (Details) (USD $)	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010
Schedule of Non-Covered Loans Receivable [Line Items]
Loans receivable, excluding covered loans, gross	$ 9,339,257,000		$ 8,717,388,000
Unearned fees, premiums and discounts, net	(24,258,000)		(56,781,000)
Allowance for non-covered loans receivable	(213,825,000)		(230,408,000)
Non-covered loans receivable, excluding covered loans, net	9,101,174,000		8,430,199,000
Accrued interest on covered and non-covered loans receivable	68,700,000		65,600,000
Covered and non-covered loans receivable pledged to secure borrowings from the FHLB and the Federal Reserve Bank	8,130,000,000		8,140,000,000
Number of units of which residential property securing fixed and adjustable rate first mortgage loans consist, minimum	1
Number of units of which residential property securing fixed and adjustable rate first mortgage loans consist, maximum	4
Amount of new first mortgage loans originated on single-family residential properties	294,700,000	181,100,000
Amount of new first mortgage loans originated on multifamily residential properties	23,900,000	10,300,000
Adjustable rate mortgage, term of initial fixed interest rates, minimum (in months)	6M
Adjustable rate mortgage, term of initial fixed interest rates, midrange (in years)	3Y
Adjustable rate mortgage, term of initial fixed interest rates, maximum (in years)	5Y
Amount of single-family mortgage loans with interest-only features	7,100,000		7,800,000
Ratio of single-family mortgage loans with interest-only features to total single-family loans (in hundredths)	1.00%		1.00%
Amount of acquired residential mortgage loans with variable payment option features	16,400,000		16,900,000
Ratio of residential mortgage loans with variable payment option features to total residential mortgage loans (in hundredths)	1.00%		1.00%
Credit Risk and Concentrations [Abstract]
Percentage of non-covered loans secured by real properties located in California (in hundredths)	94.00%
Purchased Loans [Abstract]
Loans acquired during the period	464,000,000
Carrying amount of student loans acquired during the period	426,200,000
Loans Held for Sale [Abstract]
Total loans held for sale	326,841,000		220,055,000
Percentage of loans held for sale that were student loans reclassified to loans held for sale during the period (in hundredths)	91.00%
Proceeds from sale of loans held for sale during the period	376,600,000	260,700,000
Net gain from sale of loans held for sale during the period	10,200,000	8,100,000
Loans held for sale in short-term call option to sell	235,100,000
Residential [Member]
Schedule of Non-Covered Loans Receivable [Line Items]
Loans receivable, excluding covered loans, gross	2,237,216,000		2,093,769,000
Residential [Member] | Single-family [Member]
Schedule of Non-Covered Loans Receivable [Line Items]
Loans receivable, excluding covered loans, gross	1,286,235,000		1,119,024,000
Residential [Member] | Multifamily [Member]
Schedule of Non-Covered Loans Receivable [Line Items]
Loans receivable, excluding covered loans, gross	950,981,000		974,745,000
Commercial Real Estate [Member]
Schedule of Non-Covered Loans Receivable [Line Items]
Loans receivable, excluding covered loans, gross	3,828,629,000		3,906,738,000
Commercial Real Estate [Member] | Income Producing [Member]
Schedule of Non-Covered Loans Receivable [Line Items]
Loans receivable, excluding covered loans, gross	3,408,560,000		3,392,984,000
Commercial Real Estate [Member] | Construction [Member]
Schedule of Non-Covered Loans Receivable [Line Items]
Loans receivable, excluding covered loans, gross	216,690,000		278,047,000
Commercial Real Estate [Member] | Land CRE [Member]
Schedule of Non-Covered Loans Receivable [Line Items]
Loans receivable, excluding covered loans, gross	203,380,000		235,707,000
Commercial and Industrial [Member]
Schedule of Non-Covered Loans Receivable [Line Items]
Loans receivable, excluding covered loans, gross	2,684,472,000		1,983,355,000
Commercial and Industrial [Member] | Commercial Business [Member]
Schedule of Non-Covered Loans Receivable [Line Items]
Loans receivable, excluding covered loans, gross	2,283,917,000		1,674,698,000
Commercial and Industrial [Member] | Trade Finance [Member]
Schedule of Non-Covered Loans Receivable [Line Items]
Loans receivable, excluding covered loans, gross	400,555,000		308,657,000
Consumer [Member]
Schedule of Non-Covered Loans Receivable [Line Items]
Loans receivable, excluding covered loans, gross	588,940,000		733,526,000
Consumer [Member] | Student Loans [Member]
Schedule of Non-Covered Loans Receivable [Line Items]
Loans receivable, excluding covered loans, gross	358,378,000		490,314,000
Consumer [Member] | Other Consumer [Member]
Schedule of Non-Covered Loans Receivable [Line Items]
Loans receivable, excluding covered loans, gross	$ 230,562,000		$ 243,212,000