LOANS AND LEASES AND ALLOWANCE FOR LOAN AND LEASE LOSSES - Aging of Recorded Investment in Past Due Loans and Leases (Detail) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	$ 50,744	$ 46,421
60 - 89 Days Past Due	13,427	11,914
Greater than 89 Days Past due	31,503	22,596
Total Past Due	95,674	80,931
Current	4,377,421	3,868,191
Total ending loan balances	4,473,095	3,949,122	$ 2,602,213
Single family residential mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	1,723,043	1,048,485
Consumer Home Equity Loan \| Green Loans (HELOC) - first liens
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	117,881	123,177
Consumer Home Equity Loan \| Green Loans (HELOC) - second liens
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	4,773	4,979
Other consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	131,909	161,939
Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	771,477	490,900	368,540
Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	807,146	999,857	535,744
Multi-family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	696,768	955,683	234,179
SBA
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	56,887	36,155	28,684
Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	32,022	42,198	30,761
Lease financing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	131,189	85,749	$ 57,754
Purchased Credit Impaired
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	13,629	14,140
60 - 89 Days Past Due	3,722	3,501
Greater than 89 Days Past due	8,648	5,761
Total Past Due	25,999	23,402
Current	240,373	223,495
Total ending loan balances	266,372	246,897
Purchased Credit Impaired \| Single family residential mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	13,257	13,262
60 - 89 Days Past Due	3,531	3,501
Greater than 89 Days Past due	7,154	4,510
Total Past Due	23,942	21,273
Current	228,040	209,806
Total ending loan balances	251,982	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	0	0
60 - 89 Days Past Due	0	0
Greater than 89 Days Past due	184	0
Total Past Due	184	0
Current	181	1,134
Total ending loan balances	365	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	691	951
Total Past Due	691	951
Current	10,313	10,576
Total ending loan balances	11,004	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	372	878
60 - 89 Days Past Due	191	0
Greater than 89 Days Past due	619	300
Total Past Due	1,182	1,178
Current	1,839	1,979
Total ending loan balances	3,021	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	13,709	10,562
60 - 89 Days Past Due	2,392	165
Greater than 89 Days Past due	4,014	2,695
Total Past Due	20,115	13,422
Current	700,206	337,153
Total ending loan balances	720,321	350,575
Non-Traditional Mortgages (NTM) \| Green Loans (HELOC) - first liens
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	715,435	345,483
Non-Traditional Mortgages (NTM) \| Green Loans (HELOC) - second liens
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total ending loan balances	4,886	5,092
Non-Traditional Mortgages (NTM) \| Single family residential mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	5,637	1,415
60 - 89 Days Past Due	170	165
Greater than 89 Days Past due	4,014	2,049
Total Past Due	9,821	3,629
Current	587,733	218,677
Total ending loan balances	597,554	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	8,072	8,853
60 - 89 Days Past Due	2,222	0
Greater than 89 Days Past due	0	437
Total Past Due	10,294	9,290
Current	107,587	113,887
Total ending loan balances	117,881	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	4,773	4,476
Total ending loan balances	4,773	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	23,406	21,719
60 - 89 Days Past Due	7,313	8,248
Greater than 89 Days Past due	18,841	14,140
Total Past Due	49,560	44,107
Current	3,436,842	3,307,543
Total ending loan balances	3,486,402	3,351,650
Traditional Loans \| Single family residential mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	18,509	17,185
60 - 89 Days Past Due	6,698	7,878
Greater than 89 Days Past due	17,491	10,411
Total Past Due	42,698	35,474
Current	830,809	559,626
Total ending loan balances	873,507	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	132	9
60 - 89 Days Past Due	0	89
Greater than 89 Days Past due	27	5
Total Past Due	159	103
Current	131,637	161,723
Total ending loan balances	131,796	161,826
Traditional Loans \| Commercial and industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	1,053	79
60 - 89 Days Past Due	14	37
Greater than 89 Days Past due	169	3,370
Total Past Due	1,236	3,486
Current	769,876	486,280
Total ending loan balances	771,112	489,766
Traditional Loans \| Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	2,900	2,237
60 - 89 Days Past Due	358	0
Greater than 89 Days Past due	0	0
Total Past Due	3,258	2,237
Current	792,884	986,093
Total ending loan balances	796,142	988,330
Traditional Loans \| Multi-family
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	335	1,072
60 - 89 Days Past Due	0	208
Greater than 89 Days Past due	0	0
Total Past Due	335	1,280
Current	696,433	954,403
Total ending loan balances	696,768	955,683
Traditional Loans \| SBA
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	30	82
60 - 89 Days Past Due	0	0
Greater than 89 Days Past due	230	254
Total Past Due	260	336
Current	53,606	32,662
Total ending loan balances	53,866	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	32,022	42,198
Total ending loan balances	32,022	42,198
Traditional Loans \| Lease financing
Financing Receivable, Recorded Investment, Past Due [Line Items]
30 - 59 Days Past Due	447	1,055
60 - 89 Days Past Due	243	36
Greater than 89 Days Past due	924	100
Total Past Due	1,614	1,191
Current	129,575	84,558
Total ending loan balances	$ 131,189	$ 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