NON-COVERED LOANS AND ALLOWANCE FOR LOAN LOSSES (Details 4) (USD $) In Thousands, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2013 item	Dec. 31, 2012 item
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
Number of loss grade loans	0	0
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	$ 13,525,914	$ 11,958,873
Pass/Watch
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	12,797,731	11,253,469
Special Mention
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	236,880	186,560
Substandard
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	491,303	518,844
Residential
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	3,505,842	3,088,031
Residential | Residential Single-family
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	2,575,975	2,187,323
Residential | Residential Single-family | Pass/Watch
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	2,549,678	2,163,918
Residential | Residential Single-family | Special Mention
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	11,392	5,131
Residential | Residential Single-family | Substandard
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	14,905	18,274
Residential | Residential Multifamily
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	929,867	900,708
Residential | Residential Multifamily | Pass/Watch
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	843,283	781,552
Residential | Residential Multifamily | Special Mention
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	7,459	13,510
Residential | Residential Multifamily | Substandard
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	79,125	105,646
Commercial Real Estate ("CRE")
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	4,150,384	3,894,695
Commercial Real Estate ("CRE") | Income producing
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	3,917,082	3,644,035
Commercial Real Estate ("CRE") | Income producing | Pass/Watch
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	3,659,388	3,416,142
Commercial Real Estate ("CRE") | Income producing | Special Mention
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	45,802	42,222
Commercial Real Estate ("CRE") | Income producing | Substandard
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	211,892	185,671
Commercial Real Estate ("CRE") | Construction
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	105,084	121,589
Commercial Real Estate ("CRE") | Construction | Pass/Watch
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	77,327	63,008
Commercial Real Estate ("CRE") | Construction | Special Mention
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	6,160	16,885
Commercial Real Estate ("CRE") | Construction | Substandard
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	21,597	41,696
Commercial Real Estate ("CRE") | Land
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	128,218	129,071
Commercial Real Estate ("CRE") | Land | Pass/Watch
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	79,291	79,085
Commercial Real Estate ("CRE") | Land | Special Mention
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	13,043	13,232
Commercial Real Estate ("CRE") | Land | Substandard
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	35,884	36,754
Commercial and Industrial ("C&I")
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	4,709,675	4,231,265
Commercial and Industrial ("C&I") | Commercial Business
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	4,036,795	3,569,388
Commercial and Industrial ("C&I") | Commercial Business | Pass/Watch
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	3,774,340	3,380,212
Commercial and Industrial ("C&I") | Commercial Business | Special Mention
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	142,216	69,687
Commercial and Industrial ("C&I") | Commercial Business | Substandard
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	120,239	119,489
Commercial and Industrial ("C&I") | Trade finance
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	672,880	661,877
Commercial and Industrial ("C&I") | Trade finance | Pass/Watch
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	659,604	632,617
Commercial and Industrial ("C&I") | Trade finance | Special Mention
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	9,124	24,778
Commercial and Industrial ("C&I") | Trade finance | Substandard
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	4,152	4,482
Consumer
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	1,160,013	744,882
Consumer | Student loans
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	615,707	475,799
Consumer | Student loans | Pass/Watch
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	615,642	475,799
Consumer | Student loans | Special Mention
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	65
Consumer | Other Consumer
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	544,306	269,083
Consumer | Other Consumer | Pass/Watch
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	539,178	261,136
Consumer | Other Consumer | Special Mention
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	1,619	1,115
Consumer | Other Consumer | Substandard
Credit quality indicator disclosures
Loans receivable, excluding covered loans, gross	$ 3,509	$ 6,832