NON-COVERED LOANS AND ALLOWANCE FOR LOAN LOSSES (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Non-Covered loans receivable disclosures
Loans receivable, excluding covered loans, gross	$ 12,375,028	$ 11,958,873
Unearned fees, premiums and discounts, net	(26,329)	(19,301)
Allowance for non-covered loans receivable	(228,796)	(229,382)
Non-covered loans receivable, excluding covered loans, net	12,119,903	11,710,190
Residential
Non-Covered loans receivable disclosures
Loans receivable, excluding covered loans, gross	3,254,133	3,088,031
Residential | Single-family
Non-Covered loans receivable disclosures
Loans receivable, excluding covered loans, gross	2,334,913	2,187,323
Residential | Multifamily
Non-Covered loans receivable disclosures
Loans receivable, excluding covered loans, gross	919,220	900,708
Commercial Real Estate ("CRE")
Non-Covered loans receivable disclosures
Loans receivable, excluding covered loans, gross	3,996,312	3,894,695
Commercial Real Estate ("CRE") | Income producing
Non-Covered loans receivable disclosures
Loans receivable, excluding covered loans, gross	3,754,434	3,644,035
Commercial Real Estate ("CRE") | Construction
Non-Covered loans receivable disclosures
Loans receivable, excluding covered loans, gross	129,881	121,589
Commercial Real Estate ("CRE") | Land
Non-Covered loans receivable disclosures
Loans receivable, excluding covered loans, gross	111,997	129,071
Commercial and Industrial ("C&I")
Non-Covered loans receivable disclosures
Loans receivable, excluding covered loans, gross	4,280,789	4,231,265
Commercial and Industrial ("C&I") | Commercial Business
Non-Covered loans receivable disclosures
Loans receivable, excluding covered loans, gross	3,588,228	3,569,388
Commercial and Industrial ("C&I") | Trade finance
Non-Covered loans receivable disclosures
Loans receivable, excluding covered loans, gross	692,561	661,877
Consumer
Non-Covered loans receivable disclosures
Loans receivable, excluding covered loans, gross	843,794	744,882
Consumer | Student loans
Non-Covered loans receivable disclosures
Loans receivable, excluding covered loans, gross	562,819	475,799
Consumer | Other Consumer
Non-Covered loans receivable disclosures
Loans receivable, excluding covered loans, gross	$ 280,975	$ 269,083