NON-COVERED LOANS AND ALLOWANCE FOR LOAN LOSSES (Details 4) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2012	Dec. 31, 2011
Age analysis of past due non-covered loans and loans held for sale
Accruing loans 30 - 59 days past due	$ 51,608	$ 33,117
Accruing loans 60 - 89 days past due	9,141	7,210
Total accruing past due loans	60,749	40,327
Nonaccrual loans less than 90 days past due	18,461	45,786
Nonaccrual loans 90 or more days past due	102,337	99,846
Total nonaccrual past due loans	120,798	145,632
Current loans	10,597,396	10,381,070
Total non-covered loans and loans held for sale, gross	10,778,943	10,567,029
Unearned fees, premiums and discounts, net	(19,034)	(16,762)
Recorded investment in non-covered loans and loans held for sale	10,759,909	10,550,267
Interest Income Foregone on Nonaccrual Loans
Interest income that would have been recognized had nonaccrual loans performed in accordance with their original terms	1,730	2,765
Less: Interest income recognized on nonaccrual loans on a cash basis	(701)	(807)
Interest income foregone on nonaccrual loans	1,029	1,958
Minimum
Age analysis of past due non-covered loans and loans held for sale
Number of days past due generally required before loan is placed on nonaccrual status (in days)	90 days
Loans Held for Sale
Age analysis of past due non-covered loans and loans held for sale
Nonaccrual loans 90 or more days past due	14,242	25,655
Total nonaccrual past due loans	14,242	25,655
Current loans	266,588	252,948
Total non-covered loans and loans held for sale, gross	280,830	278,603
Residential | Single-family
Age analysis of past due non-covered loans and loans held for sale
Accruing loans 30 - 59 days past due	3,786	6,991
Accruing loans 60 - 89 days past due	216	1,198
Total accruing past due loans	4,002	8,189
Nonaccrual loans 90 or more days past due	3,735	3,569
Total nonaccrual past due loans	3,735	3,569
Current loans	1,945,386	1,784,877
Total non-covered loans and loans held for sale, gross	1,953,123	1,796,635
Residential | Multifamily
Age analysis of past due non-covered loans and loans held for sale
Accruing loans 30 - 59 days past due	4,281	6,366
Accruing loans 60 - 89 days past due	4,849	745
Total accruing past due loans	9,130	7,111
Nonaccrual loans less than 90 days past due	10,399	6,889
Nonaccrual loans 90 or more days past due	8,067	11,306
Total nonaccrual past due loans	18,466	18,195
Current loans	889,157	907,862
Total non-covered loans and loans held for sale, gross	916,753	933,168
Commercial Real Estate ("CRE") | Income producing
Age analysis of past due non-covered loans and loans held for sale
Accruing loans 30 - 59 days past due	14,696	18,179
Accruing loans 60 - 89 days past due	2,734	1,549
Total accruing past due loans	17,430	19,728
Nonaccrual loans less than 90 days past due	3,450	6,885
Nonaccrual loans 90 or more days past due	29,962	25,690
Total nonaccrual past due loans	33,412	32,575
Current loans	3,403,799	3,435,563
Total non-covered loans and loans held for sale, gross	3,454,641	3,487,866
Commercial Real Estate ("CRE") | Construction
Age analysis of past due non-covered loans and loans held for sale
Nonaccrual loans less than 90 days past due		26,482
Nonaccrual loans 90 or more days past due	25,832	14,688
Total nonaccrual past due loans	25,832	41,170
Current loans	126,747	130,240
Total non-covered loans and loans held for sale, gross	152,579	171,410
Commercial Real Estate ("CRE") | Land
Age analysis of past due non-covered loans and loans held for sale
Accruing loans 30 - 59 days past due	12,750
Accruing loans 60 - 89 days past due	579	573
Total accruing past due loans	13,329	573
Nonaccrual loans less than 90 days past due	530	1,136
Nonaccrual loans 90 or more days past due	8,477	9,589
Total nonaccrual past due loans	9,007	10,725
Current loans	147,318	161,791
Total non-covered loans and loans held for sale, gross	169,654	173,089
Commercial and Industrial ("C&I") | Commercial Business
Age analysis of past due non-covered loans and loans held for sale
Accruing loans 30 - 59 days past due	14,692	342
Accruing loans 60 - 89 days past due	543	2,957
Total accruing past due loans	15,235	3,299
Nonaccrual loans less than 90 days past due	4,082	4,394
Nonaccrual loans 90 or more days past due	6,806	6,843
Total nonaccrual past due loans	10,888	11,237
Current loans	2,759,848	2,641,381
Total non-covered loans and loans held for sale, gross	2,785,971	2,655,917
Commercial and Industrial ("C&I") | Trade finance
Age analysis of past due non-covered loans and loans held for sale
Nonaccrual loans 90 or more days past due	2,042
Total nonaccrual past due loans	2,042
Current loans	450,592	486,555
Total non-covered loans and loans held for sale, gross	452,634	486,555
Consumer | Student loans
Age analysis of past due non-covered loans and loans held for sale
Accruing loans 30 - 59 days past due	157	109
Accruing loans 60 - 89 days past due	50	188
Total accruing past due loans	207	297
Nonaccrual loans 90 or more days past due	782	257
Total nonaccrual past due loans	782	257
Current loans	340,977	305,771
Total non-covered loans and loans held for sale, gross	341,966	306,325
Consumer | Other Consumer
Age analysis of past due non-covered loans and loans held for sale
Accruing loans 30 - 59 days past due	1,246	1,130
Accruing loans 60 - 89 days past due	170
Total accruing past due loans	1,416	1,130
Nonaccrual loans 90 or more days past due	2,392	2,249
Total nonaccrual past due loans	2,392	2,249
Current loans	266,984	274,082
Total non-covered loans and loans held for sale, gross	$ 270,792	$ 277,461