LOANS AND LEASES AND ALLOWANCE FOR LOAN AND LEASE LOSSES - Risk Categories for Loans and Leases (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015
Financing Receivable, Recorded Investment [Line Items]
Loans	$ 6,568,791	$ 5,184,394	$ 4,730,077
Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	5,868,682	4,376,684
Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	17,453	36,530
Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	50,309	72,089
Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans	81	0
Not-Rated
Financing Receivable, Recorded Investment [Line Items]
Loans	632,266	699,091
Purchased Credit Impaired
Financing Receivable, Recorded Investment [Line Items]
Loans	642,367	712,731	372,557
Purchased Credit Impaired | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	2,006	6,663
Purchased Credit Impaired | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	4,561	523
Purchased Credit Impaired | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	3,534	6,454
Purchased Credit Impaired | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Purchased Credit Impaired | Not-Rated
Financing Receivable, Recorded Investment [Line Items]
Loans	632,266	699,091
Non-Traditional Mortgages (NTM)
Financing Receivable, Recorded Investment [Line Items]
Loans	891,083	785,908
Traditional Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	5,035,341	3,685,755
Traditional Loans | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	4,990,799	3,616,554
Traditional Loans | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	9,076	21,947
Traditional Loans | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	35,385	47,254
Traditional Loans | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans	81	0
Traditional Loans | Not-Rated
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Traditional Loans | Construction
Financing Receivable, Recorded Investment [Line Items]
Loans	99,086	55,289
Consumer | Single family residential mortgage
Financing Receivable, Recorded Investment [Line Items]
Loans	2,503,927	2,150,453
Consumer | Other consumer
Financing Receivable, Recorded Investment [Line Items]
Loans	110,258	109,681
Consumer | Purchased Credit Impaired | Single family residential mortgage
Financing Receivable, Recorded Investment [Line Items]
Loans	632,393	699,230
Consumer | Purchased Credit Impaired | Single family residential mortgage | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Consumer | Purchased Credit Impaired | Single family residential mortgage | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Consumer | Purchased Credit Impaired | Single family residential mortgage | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	127	139
Consumer | Purchased Credit Impaired | Single family residential mortgage | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Consumer | Purchased Credit Impaired | Single family residential mortgage | Not-Rated
Financing Receivable, Recorded Investment [Line Items]
Loans	632,266	699,091
Consumer | Purchased Credit Impaired | Other consumer
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Consumer | Non-Traditional Mortgages (NTM)
Financing Receivable, Recorded Investment [Line Items]
Loans	891,083	785,908
Consumer | Non-Traditional Mortgages (NTM) | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	875,877	753,467
Consumer | Non-Traditional Mortgages (NTM) | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	3,816	14,060
Consumer | Non-Traditional Mortgages (NTM) | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	11,390	18,381
Consumer | Non-Traditional Mortgages (NTM) | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Consumer | Non-Traditional Mortgages (NTM) | Not-Rated
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Consumer | Non-Traditional Mortgages (NTM) | Green Loans (HELOC) - first liens
Financing Receivable, Recorded Investment [Line Items]
Loans	887,374	781,091
Consumer | Non-Traditional Mortgages (NTM) | Green Loans (HELOC) - second liens
Financing Receivable, Recorded Investment [Line Items]
Loans	3,709	4,817
Consumer | Non-Traditional Mortgages (NTM) | Single family residential mortgage
Financing Receivable, Recorded Investment [Line Items]
Loans	789,926	675,960
Consumer | Non-Traditional Mortgages (NTM) | Single family residential mortgage | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	785,419	660,683
Consumer | Non-Traditional Mortgages (NTM) | Single family residential mortgage | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	1,806	11,731
Consumer | Non-Traditional Mortgages (NTM) | Single family residential mortgage | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	2,701	3,546
Consumer | Non-Traditional Mortgages (NTM) | Single family residential mortgage | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Consumer | Non-Traditional Mortgages (NTM) | Single family residential mortgage | Not-Rated
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Consumer | Non-Traditional Mortgages (NTM) | Consumer Home Equity Loan | Green Loans (HELOC) - first liens
Financing Receivable, Recorded Investment [Line Items]
Loans	97,448	105,131
Consumer | Non-Traditional Mortgages (NTM) | Consumer Home Equity Loan | Green Loans (HELOC) - first liens | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	86,749	87,967
Consumer | Non-Traditional Mortgages (NTM) | Consumer Home Equity Loan | Green Loans (HELOC) - first liens | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	2,010	2,329
Consumer | Non-Traditional Mortgages (NTM) | Consumer Home Equity Loan | Green Loans (HELOC) - first liens | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	8,689	14,835
Consumer | Non-Traditional Mortgages (NTM) | Consumer Home Equity Loan | Green Loans (HELOC) - first liens | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Consumer | Non-Traditional Mortgages (NTM) | Consumer Home Equity Loan | Green Loans (HELOC) - first liens | Not-Rated
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Consumer | Non-Traditional Mortgages (NTM) | Consumer Home Equity Loan | Green Loans (HELOC) - second liens
Financing Receivable, Recorded Investment [Line Items]
Loans	3,709	4,704
Consumer | Non-Traditional Mortgages (NTM) | Consumer Home Equity Loan | Green Loans (HELOC) - second liens | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	3,709	4,704
Consumer | Non-Traditional Mortgages (NTM) | Consumer Home Equity Loan | Green Loans (HELOC) - second liens | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Consumer | Non-Traditional Mortgages (NTM) | Consumer Home Equity Loan | Green Loans (HELOC) - second liens | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Consumer | Non-Traditional Mortgages (NTM) | Consumer Home Equity Loan | Green Loans (HELOC) - second liens | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Consumer | Non-Traditional Mortgages (NTM) | Consumer Home Equity Loan | Green Loans (HELOC) - second liens | Not-Rated
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Consumer | Non-Traditional Mortgages (NTM) | Other consumer
Financing Receivable, Recorded Investment [Line Items]
Loans	0	113
Consumer | Non-Traditional Mortgages (NTM) | Other consumer | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	0	113
Consumer | Non-Traditional Mortgages (NTM) | Other consumer | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Consumer | Non-Traditional Mortgages (NTM) | Other consumer | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Consumer | Non-Traditional Mortgages (NTM) | Other consumer | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Consumer | Non-Traditional Mortgages (NTM) | Other consumer | Not-Rated
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Consumer | Traditional Loans
Financing Receivable, Recorded Investment [Line Items]
Loans		3,685,755
Consumer | Traditional Loans | Single family residential mortgage
Financing Receivable, Recorded Investment [Line Items]
Loans	1,081,608	775,263
Consumer | Traditional Loans | Single family residential mortgage | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	1,059,199	738,196
Consumer | Traditional Loans | Single family residential mortgage | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	4,855	12,301
Consumer | Traditional Loans | Single family residential mortgage | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	17,554	24,766
Consumer | Traditional Loans | Single family residential mortgage | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Consumer | Traditional Loans | Single family residential mortgage | Not-Rated
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Consumer | Traditional Loans | Other consumer
Financing Receivable, Recorded Investment [Line Items]
Loans	110,258	109,568
Consumer | Traditional Loans | Other consumer | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	108,976	109,206
Consumer | Traditional Loans | Other consumer | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	49	148
Consumer | Traditional Loans | Other consumer | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	1,233	214
Consumer | Traditional Loans | Other consumer | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Consumer | Traditional Loans | Other consumer | Not-Rated
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Commercial | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Loans	1,531,041	876,999	822,690
Commercial | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Loans	721,838	727,707	690,862
Commercial | Multi-family
Financing Receivable, Recorded Investment [Line Items]
Loans	1,199,207	904,300	823,415
Commercial | SBA
Financing Receivable, Recorded Investment [Line Items]
Loans	67,737	57,706	52,985
Commercial | Construction
Financing Receivable, Recorded Investment [Line Items]
Loans	99,086	55,289	39,475
Commercial | Lease financing
Financing Receivable, Recorded Investment [Line Items]
Loans	234,540	192,424	162,504
Commercial | Purchased Credit Impaired | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Loans	4,796	853	456
Commercial | Purchased Credit Impaired | Commercial and industrial | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	13	54
Commercial | Purchased Credit Impaired | Commercial and industrial | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	4,052	0
Commercial | Purchased Credit Impaired | Commercial and industrial | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	731	799
Commercial | Purchased Credit Impaired | Commercial and industrial | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Commercial | Purchased Credit Impaired | Commercial and industrial | Not-Rated
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Commercial | Purchased Credit Impaired | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Loans	2,418	9,599	10,490
Commercial | Purchased Credit Impaired | Commercial real estate | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	703	5,621
Commercial | Purchased Credit Impaired | Commercial real estate | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	509	523
Commercial | Purchased Credit Impaired | Commercial real estate | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	1,206	3,455
Commercial | Purchased Credit Impaired | Commercial real estate | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Commercial | Purchased Credit Impaired | Commercial real estate | Not-Rated
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Commercial | Purchased Credit Impaired | Multi-family
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0	0
Commercial | Purchased Credit Impaired | SBA
Financing Receivable, Recorded Investment [Line Items]
Loans	2,760	3,049	3,123
Commercial | Purchased Credit Impaired | SBA | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	1,290	988
Commercial | Purchased Credit Impaired | SBA | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Commercial | Purchased Credit Impaired | SBA | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	1,470	2,061
Commercial | Purchased Credit Impaired | SBA | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Commercial | Purchased Credit Impaired | SBA | Not-Rated
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Commercial | Purchased Credit Impaired | Construction
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0	0
Commercial | Purchased Credit Impaired | Lease financing
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0	$ 0
Commercial | Non-Traditional Mortgages (NTM) | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Commercial | Non-Traditional Mortgages (NTM) | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Commercial | Non-Traditional Mortgages (NTM) | Multi-family
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Commercial | Non-Traditional Mortgages (NTM) | SBA
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Commercial | Non-Traditional Mortgages (NTM) | Construction
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Commercial | Non-Traditional Mortgages (NTM) | Lease financing
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Commercial | Traditional Loans | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Loans	1,526,245	876,146
Commercial | Traditional Loans | Commercial and industrial | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	1,514,194	860,993
Commercial | Traditional Loans | Commercial and industrial | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	852	3,175
Commercial | Traditional Loans | Commercial and industrial | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	11,118	11,978
Commercial | Traditional Loans | Commercial and industrial | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans	81	0
Commercial | Traditional Loans | Commercial and industrial | Not-Rated
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Commercial | Traditional Loans | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Loans	719,420	718,108
Commercial | Traditional Loans | Commercial real estate | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	714,884	707,238
Commercial | Traditional Loans | Commercial real estate | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	1,791	4,788
Commercial | Traditional Loans | Commercial real estate | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	2,745	6,082
Commercial | Traditional Loans | Commercial real estate | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Commercial | Traditional Loans | Commercial real estate | Not-Rated
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Commercial | Traditional Loans | Multi-family
Financing Receivable, Recorded Investment [Line Items]
Loans	1,199,207	904,300
Commercial | Traditional Loans | Multi-family | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	1,199,207	901,578
Commercial | Traditional Loans | Multi-family | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	0	403
Commercial | Traditional Loans | Multi-family | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	0	2,319
Commercial | Traditional Loans | Multi-family | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Commercial | Traditional Loans | Multi-family | Not-Rated
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Commercial | Traditional Loans | SBA
Financing Receivable, Recorded Investment [Line Items]
Loans	64,977	54,657
Commercial | Traditional Loans | SBA | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	64,596	53,078
Commercial | Traditional Loans | SBA | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	0	1,132
Commercial | Traditional Loans | SBA | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	381	447
Commercial | Traditional Loans | SBA | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Commercial | Traditional Loans | SBA | Not-Rated
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Commercial | Traditional Loans | Construction
Financing Receivable, Recorded Investment [Line Items]
Loans	99,086	55,289
Commercial | Traditional Loans | Construction | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	97,557	55,289
Commercial | Traditional Loans | Construction | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	1,529	0
Commercial | Traditional Loans | Construction | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Commercial | Traditional Loans | Construction | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Commercial | Traditional Loans | Construction | Not-Rated
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Commercial | Traditional Loans | Lease financing
Financing Receivable, Recorded Investment [Line Items]
Loans	234,540	192,424
Commercial | Traditional Loans | Lease financing | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	232,186	190,976
Commercial | Traditional Loans | Lease financing | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Commercial | Traditional Loans | Lease financing | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	2,354	1,448
Commercial | Traditional Loans | Lease financing | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Commercial | Traditional Loans | Lease financing | Not-Rated
Financing Receivable, Recorded Investment [Line Items]
Loans	$ 0	$ 0