LOANS AND LEASES AND ALLOWANCE FOR LOAN AND LEASE LOSSES - Aging of Recorded Investment in Past Due Loans and Leases (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	$ 47,566	$ 46,421
60 - 89 Days Past Due	9,450	11,914
Greater than 89 Days Past due	27,524	22,596
Total Past Due	84,540	80,931
Current	3,849,175	3,868,191
Total ending loan balances	3,933,715	3,949,122	2,396,995
Single family residential mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	1,049,176	1,048,485
Consumer Home Equity Loan \| Green Loans (HELOC) - first liens
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	119,958	123,177
Consumer Home Equity Loan \| Green Loans (HELOC) - second liens
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	4,748	4,979
Other consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	166,470	161,939
Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	489,229	490,900	299,184
Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	975,734	999,857	560,581
Multi-family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	940,053	955,683	155,382
SBA
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	48,254	36,155	26,541
Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	38,081	42,198	25,144
Lease financing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	102,012	85,749	48,537
Purchased Credit Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	13,267	14,140
60 - 89 Days Past Due	3,108	3,501
Greater than 89 Days Past due	6,986	5,761
Total Past Due	23,361	23,402
Current	218,437	223,495
Total ending loan balances	241,798	246,897
Purchased Credit Impaired \| Single family residential mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	11,863	13,262
60 - 89 Days Past Due	3,100	3,501
Greater than 89 Days Past due	5,315	4,510
Total Past Due	20,278	21,273
Current	206,873	209,806
Total ending loan balances	227,151	231,079
Purchased Credit Impaired \| Consumer Home Equity Loan \| Green Loans (HELOC) - first liens
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	0	0
Purchased Credit Impaired \| Consumer Home Equity Loan \| Green Loans (HELOC) - second liens
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	0	0
Purchased Credit Impaired \| Other consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	0	0
Purchased Credit Impaired \| Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	736	0
60 - 89 Days Past Due	0	0
Greater than 89 Days Past due	0	0
Total Past Due	736	0
Current	343	1,134
Total ending loan balances	1,079	1,134
Purchased Credit Impaired \| Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	0	0
60 - 89 Days Past Due	0	0
Greater than 89 Days Past due	1,055	951
Total Past Due	1,055	951
Current	9,377	10,576
Total ending loan balances	10,432	11,527
Purchased Credit Impaired \| Multi-family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	0	0
Purchased Credit Impaired \| SBA
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	668	878
60 - 89 Days Past Due	8	0
Greater than 89 Days Past due	616	300
Total Past Due	1,292	1,178
Current	1,844	1,979
Total ending loan balances	3,136	3,157
Purchased Credit Impaired \| Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	0	0
Purchased Credit Impaired \| Lease financing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	0	0
Non-Traditional Mortgages (NTM)
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	10,197	10,562
60 - 89 Days Past Due	419	165
Greater than 89 Days Past due	2,957	2,695
Total Past Due	13,573	13,422
Current	340,252	337,153
Total ending loan balances	353,825	350,575
Non-Traditional Mortgages (NTM) \| Green Loans (HELOC) - first liens
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	348,964	345,483
Non-Traditional Mortgages (NTM) \| Green Loans (HELOC) - second liens
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	4,861	5,092
Non-Traditional Mortgages (NTM) \| Single family residential mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	1,121	1,415
60 - 89 Days Past Due	419	165
Greater than 89 Days Past due	2,957	2,049
Total Past Due	4,497	3,629
Current	224,509	218,677
Total ending loan balances	229,006	222,306
Non-Traditional Mortgages (NTM) \| Consumer Home Equity Loan \| Green Loans (HELOC) - first liens
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	9,076	8,853
60 - 89 Days Past Due	0	0
Greater than 89 Days Past due	0	437
Total Past Due	9,076	9,290
Current	110,882	113,887
Total ending loan balances	119,958	123,177
Non-Traditional Mortgages (NTM) \| Consumer Home Equity Loan \| Green Loans (HELOC) - second liens
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	0	294
60 - 89 Days Past Due	0	0
Greater than 89 Days Past due	0	209
Total Past Due	0	503
Current	4,748	4,476
Total ending loan balances	4,748	4,979
Non-Traditional Mortgages (NTM) \| Other consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	0	0
60 - 89 Days Past Due	0	0
Greater than 89 Days Past due	0	0
Total Past Due	0	0
Current	113	113
Total ending loan balances	113	113
Non-Traditional Mortgages (NTM) \| Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	0	0
Non-Traditional Mortgages (NTM) \| Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	0	0
Non-Traditional Mortgages (NTM) \| Multi-family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	0	0
Non-Traditional Mortgages (NTM) \| SBA
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	0	0
Non-Traditional Mortgages (NTM) \| Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	0	0
Non-Traditional Mortgages (NTM) \| Lease financing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	0	0
Traditional Loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	24,102	21,719
60 - 89 Days Past Due	5,923	8,248
Greater than 89 Days Past due	17,581	14,140
Total Past Due	47,606	44,107
Current	3,290,486	3,307,543
Total ending loan balances	3,338,092	3,351,650
Traditional Loans \| Single family residential mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	17,453	17,185
60 - 89 Days Past Due	2,765	7,878
Greater than 89 Days Past due	15,574	10,411
Total Past Due	35,792	35,474
Current	557,227	559,626
Total ending loan balances	593,019	595,100
Traditional Loans \| Consumer Home Equity Loan \| Green Loans (HELOC) - first liens
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	0	0
Traditional Loans \| Consumer Home Equity Loan \| Green Loans (HELOC) - second liens
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	0	0
Traditional Loans \| Other consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	1,150	9
60 - 89 Days Past Due	96	89
Greater than 89 Days Past due	0	5
Total Past Due	1,246	103
Current	165,111	161,723
Total ending loan balances	166,357	161,826
Traditional Loans \| Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	601	79
60 - 89 Days Past Due	16	37
Greater than 89 Days Past due	170	3,370
Total Past Due	787	3,486
Current	487,363	486,280
Total ending loan balances	488,150	489,766
Traditional Loans \| Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	3,230	2,237
60 - 89 Days Past Due	495	0
Greater than 89 Days Past due	653	0
Total Past Due	4,378	2,237
Current	960,924	986,093
Total ending loan balances	965,302	988,330
Traditional Loans \| Multi-family
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	629	1,072
60 - 89 Days Past Due	2,487	208
Greater than 89 Days Past due	207	0
Total Past Due	3,323	1,280
Current	936,730	954,403
Total ending loan balances	940,053	955,683
Traditional Loans \| SBA
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	6	82
60 - 89 Days Past Due	0	0
Greater than 89 Days Past due	314	254
Total Past Due	320	336
Current	44,798	32,662
Total ending loan balances	45,118	32,998
Traditional Loans \| Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	0	0
60 - 89 Days Past Due	0	0
Greater than 89 Days Past due	0	0
Total Past Due	0	0
Current	38,081	42,198
Total ending loan balances	38,081	42,198
Traditional Loans \| Lease financing
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	1,033	1,055
60 - 89 Days Past Due	64	36
Greater than 89 Days Past due	663	100
Total Past Due	1,760	1,191
Current	100,252	84,558
Total ending loan balances	$ 102,012	$ 85,749

LOANS AND LEASES AND ALLOWANCE FOR LOAN AND LEASE LOSSES - Aging of Recorded Investment in Past Due Loans and Leases (Detail) (USD $)
In Thousands, unless otherwise specified