LOANS AND LEASES AND ALLOWANCE FOR LOAN AND LEASE LOSSES - Aging of Recorded Investment in Past Due Loans and Leases (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 107,139	$ 110,469
Current	6,461,652	5,073,925
Total ending loan balances	6,568,791	5,184,394	$ 4,730,077
30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	58,660	63,754
60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	19,507	16,483
Greater than 89 Days Past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	28,972	30,232
Purchased Credit Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	45,258	47,185
Current	597,109	665,546
Total ending loan balances	642,367	712,731	372,557
Purchased Credit Impaired | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	31,624	33,893
Purchased Credit Impaired | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	7,489	6,398
Purchased Credit Impaired | Greater than 89 Days Past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	6,145	6,894
Non-Traditional Mortgages (NTM)
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	891,083	785,908
Traditional Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	45,272
Current	4,990,069
Total ending loan balances	5,035,341	3,685,755
Traditional Loans | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	21,154
Traditional Loans | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	3,992
Traditional Loans | Greater than 89 Days Past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	20,126
Traditional Loans | Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	99,086	55,289
Consumer | Single family residential mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	2,503,927	2,150,453
Consumer | Other consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	110,258	109,681
Consumer | Purchased Credit Impaired | Single family residential mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	44,004	44,414
Current	588,389	654,816
Total ending loan balances	632,393	699,230
Consumer | Purchased Credit Impaired | Single family residential mortgage | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	31,109	33,507
Consumer | Purchased Credit Impaired | Single family residential mortgage | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	7,489	6,235
Consumer | Purchased Credit Impaired | Single family residential mortgage | Greater than 89 Days Past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	5,406	4,672
Consumer | Purchased Credit Impaired | Other consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	0	0
Consumer | Non-Traditional Mortgages (NTM)
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	16,609	15,295
Current	874,474	770,613
Total ending loan balances	891,083	785,908
Consumer | Non-Traditional Mortgages (NTM) | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	5,882	11,848
Consumer | Non-Traditional Mortgages (NTM) | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	8,026	0
Consumer | Non-Traditional Mortgages (NTM) | Greater than 89 Days Past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,701	3,447
Consumer | Non-Traditional Mortgages (NTM) | Green Loans (HELOC) - first liens
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	887,374	781,091
Consumer | Non-Traditional Mortgages (NTM) | Green Loans (HELOC) - second liens
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	3,709	4,817
Consumer | Non-Traditional Mortgages (NTM) | Single family residential mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	8,915	7,382
Current	781,011	668,578
Total ending loan balances	789,926	675,960
Consumer | Non-Traditional Mortgages (NTM) | Single family residential mortgage | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	5,882	3,935
Consumer | Non-Traditional Mortgages (NTM) | Single family residential mortgage | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	332	0
Consumer | Non-Traditional Mortgages (NTM) | Single family residential mortgage | Greater than 89 Days Past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,701	3,447
Consumer | Non-Traditional Mortgages (NTM) | Consumer home equity loan | Green Loans (HELOC) - first liens
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	7,694	7,913
Current	89,754	97,218
Total ending loan balances	97,448	105,131
Consumer | Non-Traditional Mortgages (NTM) | Consumer home equity loan | Green Loans (HELOC) - first liens | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	7,913
Consumer | Non-Traditional Mortgages (NTM) | Consumer home equity loan | Green Loans (HELOC) - first liens | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	7,694	0
Consumer | Non-Traditional Mortgages (NTM) | Consumer home equity loan | Green Loans (HELOC) - first liens | Greater than 89 Days Past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Consumer | Non-Traditional Mortgages (NTM) | Consumer home equity loan | Green Loans (HELOC) - second liens
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Current	3,709	4,704
Total ending loan balances	3,709	4,704
Consumer | Non-Traditional Mortgages (NTM) | Consumer home equity loan | Green Loans (HELOC) - second liens | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Consumer | Non-Traditional Mortgages (NTM) | Consumer home equity loan | Green Loans (HELOC) - second liens | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Consumer | Non-Traditional Mortgages (NTM) | Consumer home equity loan | Green Loans (HELOC) - second liens | Greater than 89 Days Past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Consumer | Non-Traditional Mortgages (NTM) | Other consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Current	0	113
Total ending loan balances	0	113
Consumer | Non-Traditional Mortgages (NTM) | Other consumer | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Consumer | Non-Traditional Mortgages (NTM) | Other consumer | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Consumer | Non-Traditional Mortgages (NTM) | Other consumer | Greater than 89 Days Past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Consumer | Traditional Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		47,989
Current		3,637,766
Total ending loan balances		3,685,755
Consumer | Traditional Loans | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		18,013
Consumer | Traditional Loans | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		10,085
Consumer | Traditional Loans | Greater than 89 Days Past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due		19,891
Consumer | Traditional Loans | Single family residential mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	27,674	36,875
Current	1,053,934	738,388
Total ending loan balances	1,081,608	775,263
Consumer | Traditional Loans | Single family residential mortgage | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	11,826	15,762
Consumer | Traditional Loans | Single family residential mortgage | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,735	3,887
Consumer | Traditional Loans | Single family residential mortgage | Greater than 89 Days Past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	13,113	17,226
Consumer | Traditional Loans | Other consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	4,920	222
Current	105,338	109,346
Total ending loan balances	110,258	109,568
Consumer | Traditional Loans | Other consumer | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	3,687	0
Consumer | Traditional Loans | Other consumer | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	107	11
Consumer | Traditional Loans | Other consumer | Greater than 89 Days Past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,126	211
Commercial | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	1,531,041	876,999	822,690
Commercial | Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	721,838	727,707	690,862
Commercial | Multi-family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	1,199,207	904,300	823,415
Commercial | SBA
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	67,737	57,706	52,985
Commercial | Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	99,086	55,289	39,475
Commercial | Lease financing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	234,540	192,424	162,504
Commercial | Purchased Credit Impaired | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	164	176
Current	4,632	677
Total ending loan balances	4,796	853	456
Commercial | Purchased Credit Impaired | Commercial and industrial | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Commercial | Purchased Credit Impaired | Commercial and industrial | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Commercial | Purchased Credit Impaired | Commercial and industrial | Greater than 89 Days Past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	164	176
Commercial | Purchased Credit Impaired | Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	1,425
Current	2,418	8,174
Total ending loan balances	2,418	9,599	10,490
Commercial | Purchased Credit Impaired | Commercial real estate | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Commercial | Purchased Credit Impaired | Commercial real estate | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Commercial | Purchased Credit Impaired | Commercial real estate | Greater than 89 Days Past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	1,425
Commercial | Purchased Credit Impaired | Multi-family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	0	0	0
Commercial | Purchased Credit Impaired | SBA
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,090	1,170
Current	1,670	1,879
Total ending loan balances	2,760	3,049	3,123
Commercial | Purchased Credit Impaired | SBA | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	515	386
Commercial | Purchased Credit Impaired | SBA | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	163
Commercial | Purchased Credit Impaired | SBA | Greater than 89 Days Past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	575	621
Commercial | Purchased Credit Impaired | Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	0	0	0
Commercial | Purchased Credit Impaired | Lease financing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	0	0	$ 0
Commercial | Non-Traditional Mortgages (NTM) | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	0	0
Commercial | Non-Traditional Mortgages (NTM) | Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	0	0
Commercial | Non-Traditional Mortgages (NTM) | Multi-family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	0	0
Commercial | Non-Traditional Mortgages (NTM) | SBA
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	0	0
Commercial | Non-Traditional Mortgages (NTM) | Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	0	0
Commercial | Non-Traditional Mortgages (NTM) | Lease financing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	0	0
Commercial | Traditional Loans | Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	5,501	5,551
Current	1,520,744	870,595
Total ending loan balances	1,526,245	876,146
Commercial | Traditional Loans | Commercial and industrial | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2,015	23
Commercial | Traditional Loans | Commercial and industrial | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	50	4,984
Commercial | Traditional Loans | Commercial and industrial | Greater than 89 Days Past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	3,436	544
Commercial | Traditional Loans | Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	911
Current	719,420	717,197
Total ending loan balances	719,420	718,108
Commercial | Traditional Loans | Commercial real estate | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Commercial | Traditional Loans | Commercial real estate | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Commercial | Traditional Loans | Commercial real estate | Greater than 89 Days Past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	911
Commercial | Traditional Loans | Multi-family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	655
Current	1,199,207	903,645
Total ending loan balances	1,199,207	904,300
Commercial | Traditional Loans | Multi-family | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	223
Commercial | Traditional Loans | Multi-family | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Commercial | Traditional Loans | Multi-family | Greater than 89 Days Past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	432
Commercial | Traditional Loans | SBA
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	275	335
Current	64,702	54,322
Total ending loan balances	64,977	54,657
Commercial | Traditional Loans | SBA | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	2	0
Commercial | Traditional Loans | SBA | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	6	162
Commercial | Traditional Loans | SBA | Greater than 89 Days Past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	267	173
Commercial | Traditional Loans | Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Current	99,086	55,289
Total ending loan balances	99,086	55,289
Commercial | Traditional Loans | Construction | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Commercial | Traditional Loans | Construction | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Commercial | Traditional Loans | Construction | Greater than 89 Days Past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	0	0
Commercial | Traditional Loans | Lease financing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	6,902	3,440
Current	227,638	188,984
Total ending loan balances	234,540	192,424
Commercial | Traditional Loans | Lease financing | 30 - 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	3,624	2,005
Commercial | Traditional Loans | Lease financing | 60 - 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	1,094	1,041
Commercial | Traditional Loans | Lease financing | Greater than 89 Days Past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Past Due	$ 2,184	$ 394