LOANS AND LEASES AND ALLOWANCE FOR LOAN AND LEASE LOSSES - Risk Categories for Loans and Leases (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016
Financing Receivable, Recorded Investment [Line Items]
Loans	$ 6,105,321	$ 6,034,752	$ 5,463,068
Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	5,927,520	5,865,052
Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	17,586	12,260
Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	28,887	24,150
Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans	75	78
Not-Rated
Financing Receivable, Recorded Investment [Line Items]
Loans	131,253	133,212
Purchased Credit Impaired
Financing Receivable, Recorded Investment [Line Items]
Loans	139,699	141,826	683,976
Purchased Credit Impaired | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	2,403	2,450
Purchased Credit Impaired | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	0	4,056
Purchased Credit Impaired | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	6,043	2,108
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	131,253	133,212
Non-Traditional Mortgages (NTM)
Financing Receivable, Recorded Investment [Line Items]
Loans	818,010	885,148
Traditional Loans
Financing Receivable, Recorded Investment [Line Items]
Loans	5,147,612	5,007,778
Traditional Loans | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	5,111,057	4,981,404
Traditional Loans | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	14,104	4,721
Traditional Loans | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	22,376	21,575
Traditional Loans | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans	75	78
Traditional Loans | Not-Rated
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Traditional Loans | Construction
Financing Receivable, Recorded Investment [Line Items]
Loans	142,164	125,100
Consumer | Single family residential mortgage
Financing Receivable, Recorded Investment [Line Items]
Loans	1,889,390	2,019,161
Consumer | Other consumer
Financing Receivable, Recorded Investment [Line Items]
Loans	122,265	107,063
Consumer | Purchased Credit Impaired | Single family residential mortgage
Financing Receivable, Recorded Investment [Line Items]
Loans	131,253	133,212
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	0	0
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	131,253	133,212
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	818,010	885,148
Consumer | Non-Traditional Mortgages (NTM) | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	814,060	881,198
Consumer | Non-Traditional Mortgages (NTM) | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	3,482	3,483
Consumer | Non-Traditional Mortgages (NTM) | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	468	467
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	814,461	881,589
Consumer | Non-Traditional Mortgages (NTM) | Green Loans (HELOC) - second liens
Financing Receivable, Recorded Investment [Line Items]
Loans	3,549	3,559
Consumer | Non-Traditional Mortgages (NTM) | Single family residential mortgage
Financing Receivable, Recorded Investment [Line Items]
Loans	728,796	794,120
Consumer | Non-Traditional Mortgages (NTM) | Single family residential mortgage | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	726,854	792,179
Consumer | Non-Traditional Mortgages (NTM) | Single family residential mortgage | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	1,474	1,474
Consumer | Non-Traditional Mortgages (NTM) | Single family residential mortgage | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	468	467
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	85,665	87,469
Consumer | Non-Traditional Mortgages (NTM) | Consumer Home Equity Loan | Green Loans (HELOC) - first liens | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	83,657	85,460
Consumer | Non-Traditional Mortgages (NTM) | Consumer Home Equity Loan | Green Loans (HELOC) - first liens | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	2,008	2,009
Consumer | Non-Traditional Mortgages (NTM) | Consumer Home Equity Loan | Green Loans (HELOC) - first liens | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
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	3,549	3,559
Consumer | Non-Traditional Mortgages (NTM) | Consumer Home Equity Loan | Green Loans (HELOC) - second liens | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	3,549	3,559
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	0
Consumer | Traditional Loans | Single family residential mortgage
Financing Receivable, Recorded Investment [Line Items]
Loans	1,029,341	1,091,829
Consumer | Traditional Loans | Single family residential mortgage | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	1,017,308	1,080,664
Consumer | Traditional Loans | Single family residential mortgage | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	1,080	950
Consumer | Traditional Loans | Single family residential mortgage | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	10,953	10,215
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	122,265	107,063
Consumer | Traditional Loans | Other consumer | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	120,738	106,632
Consumer | Traditional Loans | Other consumer | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	46	48
Consumer | Traditional Loans | Other consumer | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	1,481	383
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	1,585,656	1,522,960	983,961
Commercial | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Loans	750,592	729,959	713,693
Commercial | Multi-family
Financing Receivable, Recorded Investment [Line Items]
Loans	1,449,715	1,365,262	1,021,097
Commercial | SBA
Financing Receivable, Recorded Investment [Line Items]
Loans	76,040	73,840	71,640
Commercial | Construction
Financing Receivable, Recorded Investment [Line Items]
Loans	142,164	125,100	68,241
Commercial | Lease financing
Financing Receivable, Recorded Investment [Line Items]
Loans	285	379	212,836
Commercial | Purchased Credit Impaired | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Loans	4,687	4,760	819
Commercial | Purchased Credit Impaired | Commercial and industrial | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Commercial | Purchased Credit Impaired | Commercial and industrial | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	0	4,056
Commercial | Purchased Credit Impaired | Commercial and industrial | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	4,687	704
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	1,152	1,182	8,218
Commercial | Purchased Credit Impaired | Commercial real estate | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	1,152	1,182
Commercial | Purchased Credit Impaired | Commercial real estate | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Commercial | Purchased Credit Impaired | Commercial real estate | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
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	2,607	2,672	2,940
Commercial | Purchased Credit Impaired | SBA | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	1,251	1,268
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	1,356	1,404
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	1,580,969	1,518,200
Commercial | Traditional Loans | Commercial and industrial | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	1,563,102	1,508,636
Commercial | Traditional Loans | Commercial and industrial | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	11,638	844
Commercial | Traditional Loans | Commercial and industrial | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	6,154	8,642
Commercial | Traditional Loans | Commercial and industrial | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Loans	75	78
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	749,440	728,777
Commercial | Traditional Loans | Commercial real estate | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	746,554	725,861
Commercial | Traditional Loans | Commercial real estate | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	1,340	1,350
Commercial | Traditional Loans | Commercial real estate | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	1,546	1,566
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	1,449,715	1,365,262
Commercial | Traditional Loans | Multi-family | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	1,449,715	1,365,262
Commercial | Traditional Loans | Multi-family | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Commercial | Traditional Loans | Multi-family | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
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	73,433	71,168
Commercial | Traditional Loans | SBA | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	72,816	70,508
Commercial | Traditional Loans | SBA | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	0	0
Commercial | Traditional Loans | SBA | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	617	660
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	142,164	125,100
Commercial | Traditional Loans | Construction | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	140,636	123,571
Commercial | Traditional Loans | Construction | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans	0	1,529
Commercial | Traditional Loans | Construction | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans	1,528	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	285	379
Commercial | Traditional Loans | Lease financing | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans	188	270
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	97	109
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