LOANS AND LEASES AND ALLOWANCE FOR LOAN AND LEASE LOSSES - Schedule of Loans and Leases Receivable (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Jun. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 6,568,791		$ 5,184,394	$ 4,730,077
Allowance for loan and lease losses	(40,233)	$ (37,483)	(35,533)	(34,774)	$ (34,787)	$ (29,480)
Loans and leases receivable, net	6,528,558		5,148,861
Purchased Credit Impaired
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	642,367		712,731	372,557
Allowance for loan and lease losses	(104)			(206)
Non-Traditional Mortgages (NTM)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	891,083		785,908
Traditional Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	5,035,341		3,685,755
Traditional Loans | Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	99,086		55,289
Total NTM and Traditional Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	5,926,424		4,471,663
Commercial | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,531,041		876,999	822,690
Allowance for loan and lease losses	(8,226)	(8,004)	(5,850)	(5,980)	(6,884)	(6,910)
Commercial | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	721,838		727,707	690,862
Allowance for loan and lease losses	(5,026)	(3,554)	(4,252)	(3,919)	(4,445)	(3,840)
Commercial | Multi-family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,199,207		904,300	823,415
Allowance for loan and lease losses	(8,709)	(6,914)	(6,012)	(5,710)	(3,680)	(7,179)
Commercial | SBA
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	67,737		57,706	52,985
Allowance for loan and lease losses	(908)	(697)	(683)	(615)	(674)	(335)
Commercial | Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	99,086		55,289	39,475
Allowance for loan and lease losses	(1,717)	(1,677)	(1,530)	(1,191)	(579)	(846)
Commercial | Lease financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	234,540		192,424	162,504
Allowance for loan and lease losses	(2,967)	$ (2,540)	(2,195)	(2,083)	$ (1,646)	$ (873)
Commercial | Purchased Credit Impaired | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	4,796		853	456
Allowance for loan and lease losses	(57)			(58)
Commercial | Purchased Credit Impaired | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	2,418		9,599	10,490
Allowance for loan and lease losses	(11)			(112)
Commercial | Purchased Credit Impaired | Multi-family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	0		0	0
Allowance for loan and lease losses	0			0
Commercial | Purchased Credit Impaired | SBA
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	2,760		3,049	3,123
Allowance for loan and lease losses	(19)			(19)
Commercial | Purchased Credit Impaired | Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	0		0	0
Allowance for loan and lease losses	0			0
Commercial | Purchased Credit Impaired | Lease financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	0		0	0
Allowance for loan and lease losses	0			$ 0
Commercial | Non-Traditional Mortgages (NTM) | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	0		0
Commercial | Non-Traditional Mortgages (NTM) | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	0		0
Commercial | Non-Traditional Mortgages (NTM) | Multi-family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	0		0
Commercial | Non-Traditional Mortgages (NTM) | SBA
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	0		0
Commercial | Non-Traditional Mortgages (NTM) | Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	0		0
Commercial | Non-Traditional Mortgages (NTM) | Lease financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	0		0
Commercial | Traditional Loans | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,526,245		876,146
Commercial | Traditional Loans | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	719,420		718,108
Commercial | Traditional Loans | Multi-family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,199,207		904,300
Commercial | Traditional Loans | SBA
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	64,977		54,657
Commercial | Traditional Loans | Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	99,086		55,289
Commercial | Traditional Loans | Lease financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	234,540		192,424
Commercial | Total NTM and Traditional Loans | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,526,245		876,146
Commercial | Total NTM and Traditional Loans | Commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	719,420		718,108
Commercial | Total NTM and Traditional Loans | Multi-family
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,199,207		904,300
Commercial | Total NTM and Traditional Loans | SBA
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	64,977		54,657
Commercial | Total NTM and Traditional Loans | Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	99,086		55,289
Commercial | Total NTM and Traditional Loans | Lease financing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	234,540		192,424
Consumer | Single family residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	2,503,927		2,150,453
Consumer | Home equity loan | Green Loans (HELOC) - first liens
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	97,448		105,131
Consumer | Home equity loan | Green Loans (HELOC) - second liens
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	3,709		4,704
Consumer | Other consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	110,258		109,681
Consumer | Purchased Credit Impaired | Single family residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	632,393		699,230
Consumer | Purchased Credit Impaired | Home equity loan | Green Loans (HELOC) - first liens
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	0		0
Consumer | Purchased Credit Impaired | Home equity loan | Green Loans (HELOC) - second liens
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	0		0
Consumer | Purchased Credit Impaired | Other consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	0		0
Consumer | Non-Traditional Mortgages (NTM)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	891,083		785,908
Consumer | Non-Traditional Mortgages (NTM) | Green Loans (HELOC) - first liens
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	887,374		781,091
Consumer | Non-Traditional Mortgages (NTM) | Green Loans (HELOC) - second liens
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	3,709		4,817
Consumer | Non-Traditional Mortgages (NTM) | Single family residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	789,926		675,960
Consumer | Non-Traditional Mortgages (NTM) | Home equity loan | Green Loans (HELOC) - first liens
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	97,448		105,131
Consumer | Non-Traditional Mortgages (NTM) | Home equity loan | Green Loans (HELOC) - second liens
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	3,709		4,704
Consumer | Non-Traditional Mortgages (NTM) | Other consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	0		113
Consumer | Traditional Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans			3,685,755
Consumer | Traditional Loans | Single family residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,081,608		775,263
Consumer | Traditional Loans | Home equity loan | Green Loans (HELOC) - first liens
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	0		0
Consumer | Traditional Loans | Home equity loan | Green Loans (HELOC) - second liens
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	0		0
Consumer | Traditional Loans | Other consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	110,258		109,568
Consumer | Total NTM and Traditional Loans | Single family residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,871,534		1,451,223
Consumer | Total NTM and Traditional Loans | Home equity loan | Green Loans (HELOC) - first liens
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	97,448		105,131
Consumer | Total NTM and Traditional Loans | Home equity loan | Green Loans (HELOC) - second liens
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	3,709		4,704
Consumer | Total NTM and Traditional Loans | Other consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 110,258		$ 109,681