Loans Held for Investment, net - Aging of Recorded Investment in Past Due Loans by Class of Loans (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Financing Receivable, Recorded Investment [Line Items]
Aging of the recorded investment	$ 18,000	$ 29,200
Aging of the recorded investment, Current	1,542,014	1,553,875
Total gross loans	1,560,012	1,583,105
Residential
Financing Receivable, Recorded Investment [Line Items]
Aging of the recorded investment, Current	514,895	536,228
Total gross loans	517,922	541,211
Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Aging of the recorded investment, Current	22,443	16,113
Total gross loans	22,771	16,514
Land and construction
Financing Receivable, Recorded Investment [Line Items]
Aging of the recorded investment, Current	154,731	105,029
Total gross loans	155,042	106,436
Multi-family
Financing Receivable, Recorded Investment [Line Items]
Aging of the recorded investment, Current	278,264	262,217
Total gross loans	278,264	265,735
Retail/office
Financing Receivable, Recorded Investment [Line Items]
Aging of the recorded investment, Current	138,214	152,923
Total gross loans	140,264	155,095
Other commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Aging of the recorded investment, Current	130,272	153,232
Total gross loans	130,495	156,243
Education
Financing Receivable, Recorded Investment [Line Items]
Aging of the recorded investment, Current	84,099	95,921
Total gross loans	94,944	108,384
Other consumer
Financing Receivable, Recorded Investment [Line Items]
Aging of the recorded investment, Current	219,096	232,212
Total gross loans	220,310	233,487
Days past due 30-59
Financing Receivable, Recorded Investment [Line Items]
Aging of the recorded investment	4,681	5,795
Days past due 30-59 | Residential
Financing Receivable, Recorded Investment [Line Items]
Aging of the recorded investment	379	1,186
Days past due 30-59 | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Aging of the recorded investment	178	205
Days past due 30-59 | Land and construction
Financing Receivable, Recorded Investment [Line Items]
Aging of the recorded investment	0	267
Days past due 30-59 | Multi-family
Financing Receivable, Recorded Investment [Line Items]
Aging of the recorded investment	0	0
Days past due 30-59 | Retail/office
Financing Receivable, Recorded Investment [Line Items]
Aging of the recorded investment	834	0
Days past due 30-59 | Other commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Aging of the recorded investment	0	0
Days past due 30-59 | Education
Financing Receivable, Recorded Investment [Line Items]
Aging of the recorded investment	2,663	3,505
Days past due 30-59 | Other consumer
Financing Receivable, Recorded Investment [Line Items]
Aging of the recorded investment	627	632
Days past due 60-89
Financing Receivable, Recorded Investment [Line Items]
Aging of the recorded investment	3,054	3,097
Days past due 60-89 | Residential
Financing Receivable, Recorded Investment [Line Items]
Aging of the recorded investment	1,003	802
Days past due 60-89 | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Aging of the recorded investment	0	0
Days past due 60-89 | Land and construction
Financing Receivable, Recorded Investment [Line Items]
Aging of the recorded investment	54	29
Days past due 60-89 | Multi-family
Financing Receivable, Recorded Investment [Line Items]
Aging of the recorded investment	0	0
Days past due 60-89 | Retail/office
Financing Receivable, Recorded Investment [Line Items]
Aging of the recorded investment	270	0
Days past due 60-89 | Other commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Aging of the recorded investment	41	0
Days past due 60-89 | Education
Financing Receivable, Recorded Investment [Line Items]
Aging of the recorded investment	1,652	2,140
Days past due 60-89 | Other consumer
Financing Receivable, Recorded Investment [Line Items]
Aging of the recorded investment	34	126
Days past due 90 or more
Financing Receivable, Recorded Investment [Line Items]
Aging of the recorded investment	10,263	20,338
Days past due 90 or more | Residential
Financing Receivable, Recorded Investment [Line Items]
Aging of the recorded investment	1,645	2,995
Days past due 90 or more | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Aging of the recorded investment	150	196
Days past due 90 or more | Land and construction
Financing Receivable, Recorded Investment [Line Items]
Aging of the recorded investment	257	1,111
Days past due 90 or more | Multi-family
Financing Receivable, Recorded Investment [Line Items]
Aging of the recorded investment	0	3,518
Days past due 90 or more | Retail/office
Financing Receivable, Recorded Investment [Line Items]
Aging of the recorded investment	946	2,172
Days past due 90 or more | Other commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Aging of the recorded investment	182	3,011
Days past due 90 or more | Education
Financing Receivable, Recorded Investment [Line Items]
Aging of the recorded investment	6,530	6,818
Days past due 90 or more | Other consumer
Financing Receivable, Recorded Investment [Line Items]
Aging of the recorded investment	$ 553	$ 517