NON-COVERED LOANS AND ALLOWANCE FOR LOAN LOSSES (Details 4) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012 item	Dec. 31, 2011
Credit Quality Indicators
Number of grades in the risk rating system utilized by the company to rate credit risk of loans receivable	8
Maximum term for a loan to stay graded as Special Mention	6 months
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	$ 11,155,208	$ 10,288,426
Pass/Watch
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	10,489,094	9,565,009
Special Mention
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	174,566	177,548
Substandard
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	491,548	545,622
Doubtful
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross		247
Residential
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	2,977,403	2,729,803
Residential | Residential Single-family
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	2,065,622	1,796,635
Residential | Residential Single-family | Pass/Watch
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	2,032,738	1,768,149
Residential | Residential Single-family | Special Mention
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	13,400	11,239
Residential | Residential Single-family | Substandard
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	19,484	17,247
Residential | Residential Multifamily
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	911,781	933,168
Residential | Residential Multifamily | Pass/Watch
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	802,336	810,458
Residential | Residential Multifamily | Special Mention
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	16,835	25,531
Residential | Residential Multifamily | Substandard
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	92,610	97,179
Commercial Real Estate ("CRE")
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	3,770,473	3,832,365
Commercial Real Estate ("CRE") | Income producing
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	3,519,601	3,487,866
Commercial Real Estate ("CRE") | Income producing | Pass/Watch
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	3,272,841	3,211,386
Commercial Real Estate ("CRE") | Income producing | Special Mention
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	42,346	63,066
Commercial Real Estate ("CRE") | Income producing | Substandard
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	204,414	213,414
Commercial Real Estate ("CRE") | Construction
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	110,541	171,410
Commercial Real Estate ("CRE") | Construction | Pass/Watch
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	63,316	109,184
Commercial Real Estate ("CRE") | Construction | Special Mention
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	10,773
Commercial Real Estate ("CRE") | Construction | Substandard
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	36,452	62,226
Commercial Real Estate ("CRE") | Land
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	140,331	173,089
Commercial Real Estate ("CRE") | Land | Pass/Watch
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	87,432	125,534
Commercial Real Estate ("CRE") | Land | Special Mention
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	14,677	7,954
Commercial Real Estate ("CRE") | Land | Substandard
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	38,222	39,601
Commercial and Industrial ("C&I")
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	3,732,785	3,142,472
Commercial and Industrial ("C&I") | Commercial Business
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	3,097,271	2,655,917
Commercial and Industrial ("C&I") | Commercial Business | Pass/Watch
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	2,936,048	2,492,904
Commercial and Industrial ("C&I") | Commercial Business | Special Mention
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	72,075	62,409
Commercial and Industrial ("C&I") | Commercial Business | Substandard
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	89,148	100,357
Commercial and Industrial ("C&I") | Commercial Business | Doubtful
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross		247
Commercial and Industrial ("C&I") | Trade finance
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	635,514	486,555
Commercial and Industrial ("C&I") | Trade finance | Pass/Watch
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	626,497	467,822
Commercial and Industrial ("C&I") | Trade finance | Special Mention
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	4,025	7,161
Commercial and Industrial ("C&I") | Trade finance | Substandard
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	4,992	11,572
Consumer
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	674,547	583,786
Consumer | Student loans
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	406,019	306,325
Consumer | Student loans | Pass/Watch
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	405,950	305,880
Consumer | Student loans | Special Mention
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross		188
Consumer | Student loans | Substandard
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	69	257
Consumer | Other Consumer
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	268,528	277,461
Consumer | Other Consumer | Pass/Watch
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	261,936	273,692
Consumer | Other Consumer | Special Mention
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	435
Consumer | Other Consumer | Substandard
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	$ 6,157	$ 3,769