Loans Held for Investment, net - Schedule of Average Recorded Investment in Impaired Loans and Interest Income Recognized on Impaired Loans (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2015	Dec. 31, 2014
Financing Receivable, Impaired [Line Items]
Average Carrying Amount	$ 95,451	$ 66,980	$ 93,498
Interest Income Recognized	2,097	1,989	3,579
Education
Financing Receivable, Impaired [Line Items]
Average Carrying Amount	343	104	101
Interest Income Recognized	0	0	0
Land and construction
Financing Receivable, Impaired [Line Items]
Average Carrying Amount	19,973	7,432	16,632
Interest Income Recognized	142	217	388
Multi-family
Financing Receivable, Impaired [Line Items]
Average Carrying Amount	11,456	24,416	28,444
Interest Income Recognized	233	961	1,265
Retail/office
Financing Receivable, Impaired [Line Items]
Average Carrying Amount	25,988	11,848	16,247
Interest Income Recognized	604	104	710
Residential
Financing Receivable, Impaired [Line Items]
Average Carrying Amount	18,847	12,146	14,029
Interest Income Recognized	344	456	568
Commercial and industrial
Financing Receivable, Impaired [Line Items]
Average Carrying Amount	992	79	954
Interest Income Recognized	316	3	27
Commercial real estate | Land and construction
Financing Receivable, Impaired [Line Items]
Interest Income Recognized		217
Commercial real estate | Multi-family
Financing Receivable, Impaired [Line Items]
Interest Income Recognized		961
Commercial real estate | Retail/office
Financing Receivable, Impaired [Line Items]
Interest Income Recognized		104
Commercial real estate | Other commercial real estate
Financing Receivable, Impaired [Line Items]
Average Carrying Amount	14,821	9,214	15,471
Interest Income Recognized	312	115	484
Consumer loans | Other consumer
Financing Receivable, Impaired [Line Items]
Average Carrying Amount	3,031	1,741	1,620
Interest Income Recognized	$ 146	$ 133	$ 137