LOANS RECEIVABLE AND ALLOWANCE FOR CREDIT LOSSES (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Jun. 30, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Dec. 31, 2013
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Allowance for loan losses	$ (264,430)		$ (261,679)
Loans, net	22,381,302		21,468,270
CRE
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Allowance for loan losses	(78,318)		(72,977)
C&I
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Allowance for loan losses	(138,929)		(134,598)
Residential
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Allowance for loan losses	(36,812)		(43,856)
Consumer
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Allowance for loan losses	(10,371)		(10,248)
Loans Receivable
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	22,658,908		21,727,145
Unearned fees, premiums and discounts, net	(13,176)		2,804
Allowance for loan losses	(264,430)	$ (261,229)	(261,679)	$ (253,178)	$ (251,348)	$ (249,675)
Loans, net	22,381,302		21,468,270
Loans Receivable | CRE
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	7,710,004		6,819,513
Loans Receivable | CRE | Income producing
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	7,088,408		6,256,059
Loans Receivable | CRE | Construction
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	436,197		332,287
Loans Receivable | CRE | Land
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	185,399		231,167
Loans Receivable | C&I
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	8,619,156		8,077,201
Loans Receivable | C&I | Commercial business
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	7,801,129		7,181,189
Loans Receivable | C&I | Trade finance
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	818,027		896,012
Loans Receivable | Residential
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	4,495,169		5,316,689
Loans Receivable | Residential | Single-family
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	3,002,808		3,866,781
Loans Receivable | Residential | Multifamily
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	1,492,361		1,449,908
Loans Receivable | Consumer
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	1,834,579		1,513,742
Loans Receivable | Non-PCI loans
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	21,608,903		20,405,032
Unearned fees, premiums and discounts, net	(13,176)		2,804
Allowance for loan losses	(263,889)	(260,617)	(260,965)	(252,464)	(249,790)	(247,406)
Loans, net	21,331,838		20,146,871
Loans Receivable | Non-PCI loans | Pass/Watch
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	20,864,620		19,625,603
Loans Receivable | Non-PCI loans | Special Mention
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	230,292		213,007
Loans Receivable | Non-PCI loans | Substandard
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	513,647		565,834
Loans Receivable | Non-PCI loans | Doubtful
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	344		533
Loans Receivable | Non-PCI loans | Loss
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans			55
Loans Receivable | Non-PCI loans | CRE
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	7,126,445		6,102,216
Allowance for loan losses	(77,777)	(75,496)	(72,263)	(59,675)	(60,895)	(70,154)
Loans Receivable | Non-PCI loans | CRE | Income producing
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	6,518,052		5,568,046
Loans Receivable | Non-PCI loans | CRE | Income producing | Pass/Watch
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	6,241,315		5,243,640
Loans Receivable | Non-PCI loans | CRE | Income producing | Special Mention
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	52,904		54,673
Loans Receivable | Non-PCI loans | CRE | Income producing | Substandard
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	223,833		269,733
Loans Receivable | Non-PCI loans | CRE | Construction
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	429,417		319,843
Loans Receivable | Non-PCI loans | CRE | Construction | Pass/Watch
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	425,354		310,259
Loans Receivable | Non-PCI loans | CRE | Construction | Special Mention
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans			11
Loans Receivable | Non-PCI loans | CRE | Construction | Substandard
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	4,063		9,573
Loans Receivable | Non-PCI loans | CRE | Land
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	178,976		214,327
Loans Receivable | Non-PCI loans | CRE | Land | Pass/Watch
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	160,657		185,220
Loans Receivable | Non-PCI loans | CRE | Land | Special Mention
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans			5,701
Loans Receivable | Non-PCI loans | CRE | Land | Substandard
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	18,319		23,406
Loans Receivable | Non-PCI loans | C&I
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	8,553,540		7,987,581
Allowance for loan losses	(138,929)	(133,962)	(134,598)	(135,260)	(131,057)	(115,184)
Loans Receivable | Non-PCI loans | C&I | Commercial business
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	7,739,829		7,097,853
Loans Receivable | Non-PCI loans | C&I | Commercial business | Pass/Watch
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	7,430,295		6,836,914
Loans Receivable | Non-PCI loans | C&I | Commercial business | Special Mention
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	153,160		130,319
Loans Receivable | Non-PCI loans | C&I | Commercial business | Substandard
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	156,030		130,032
Loans Receivable | Non-PCI loans | C&I | Commercial business | Doubtful
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	344		533
Loans Receivable | Non-PCI loans | C&I | Commercial business | Loss
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans			55
Loans Receivable | Non-PCI loans | C&I | Trade finance
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	813,711		889,728
Loans Receivable | Non-PCI loans | C&I | Trade finance | Pass/Watch
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	767,236		845,889
Loans Receivable | Non-PCI loans | C&I | Trade finance | Special Mention
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	17,382		13,031
Loans Receivable | Non-PCI loans | C&I | Trade finance | Substandard
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	29,093		30,808
Loans Receivable | Non-PCI loans | Residential
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	4,119,399		4,831,279
Allowance for loan losses	(36,812)	(40,668)	(43,856)	(45,197)	(45,949)	(50,716)
Loans Receivable | Non-PCI loans | Residential | Single-family
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	2,807,248		3,647,262
Loans Receivable | Non-PCI loans | Residential | Single-family | Pass/Watch
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	2,783,817		3,627,491
Loans Receivable | Non-PCI loans | Residential | Single-family | Special Mention
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	4,328		3,143
Loans Receivable | Non-PCI loans | Residential | Single-family | Substandard
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	19,103		16,628
Loans Receivable | Non-PCI loans | Residential | Multifamily
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	1,312,151		1,184,017
Loans Receivable | Non-PCI loans | Residential | Multifamily | Pass/Watch
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	1,250,706		1,095,982
Loans Receivable | Non-PCI loans | Residential | Multifamily | Special Mention
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	1,190		5,124
Loans Receivable | Non-PCI loans | Residential | Multifamily | Substandard
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	60,255		82,911
Loans Receivable | Non-PCI loans | Consumer
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	1,809,519		1,483,956
Allowance for loan losses	(10,371)	$ (10,491)	(10,248)	$ (12,332)	$ (11,889)	$ (11,352)
Loans Receivable | Non-PCI loans | Consumer | Pass/Watch
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	1,805,240		1,480,208
Loans Receivable | Non-PCI loans | Consumer | Special Mention
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	1,328		1,005
Loans Receivable | Non-PCI loans | Consumer | Substandard
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	2,951		2,743
Loans Receivable | PCI loans
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	1,050,005		1,322,113
Allowance for loan losses	(541)		(714)
Loans, net	1,049,464		1,321,399
Loans Receivable | PCI loans | Pass/Watch
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	883,582		1,089,726
Loans Receivable | PCI loans | Special Mention
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	9,376		18,688
Loans Receivable | PCI loans | Substandard
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	157,047		213,699
Loans Receivable | PCI loans | CRE
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	583,559		717,297
Loans Receivable | PCI loans | CRE | Income producing
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	570,356		688,013
Loans Receivable | PCI loans | CRE | Income producing | Pass/Watch
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	454,052		534,015
Loans Receivable | PCI loans | CRE | Income producing | Special Mention
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	7,005		9,960
Loans Receivable | PCI loans | CRE | Income producing | Substandard
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	109,299		144,038
Loans Receivable | PCI loans | CRE | Construction
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	6,780		12,444
Loans Receivable | PCI loans | CRE | Construction | Pass/Watch
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	0		589
Loans Receivable | PCI loans | CRE | Construction | Special Mention
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans			1,744
Loans Receivable | PCI loans | CRE | Construction | Substandard
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	6,780		10,111
Loans Receivable | PCI loans | CRE | Land
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	6,423		16,840
Loans Receivable | PCI loans | CRE | Land | Pass/Watch
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	4,625		7,012
Loans Receivable | PCI loans | CRE | Land | Special Mention
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans			5,391
Loans Receivable | PCI loans | CRE | Land | Substandard
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	1,798		4,437
Loans Receivable | PCI loans | C&I
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	65,616		89,620
Loans Receivable | PCI loans | C&I | Commercial business
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	61,300		83,336
Loans Receivable | PCI loans | C&I | Commercial business | Pass/Watch
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	54,899		70,586
Loans Receivable | PCI loans | C&I | Commercial business | Special Mention
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	875		1,103
Loans Receivable | PCI loans | C&I | Commercial business | Substandard
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	5,526		11,647
Loans Receivable | PCI loans | C&I | Trade finance
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	4,316		6,284
Loans Receivable | PCI loans | C&I | Trade finance | Pass/Watch
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	2,590		4,620
Loans Receivable | PCI loans | C&I | Trade finance | Substandard
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	1,726		1,664
Loans Receivable | PCI loans | Residential
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	375,770		485,410
Loans Receivable | PCI loans | Residential | Single-family
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	195,560		219,519
Loans Receivable | PCI loans | Residential | Single-family | Pass/Watch
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	190,136		213,829
Loans Receivable | PCI loans | Residential | Single-family | Special Mention
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	1,158		374
Loans Receivable | PCI loans | Residential | Single-family | Substandard
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	4,266		5,316
Loans Receivable | PCI loans | Residential | Multifamily
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	180,210		265,891
Loans Receivable | PCI loans | Residential | Multifamily | Pass/Watch
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	153,036		230,049
Loans Receivable | PCI loans | Residential | Multifamily | Special Mention
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	0
Loans Receivable | PCI loans | Residential | Multifamily | Substandard
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	27,174		35,842
Loans Receivable | PCI loans | Consumer
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	25,060		29,786
Loans Receivable | PCI loans | Consumer | Pass/Watch
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	24,244		29,026
Loans Receivable | PCI loans | Consumer | Special Mention
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	338		116
Loans Receivable | PCI loans | Consumer | Substandard
LOANS RECEIVABLE AND ALLOWANCE FOR LOAN LOSSES
Total loans	$ 478		$ 644