Loans Held for Investment, net - Loans Modified Troubled Debt Restructuring by Class (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($) LoansModifications	Dec. 31, 2014 USD ($) LoansModifications
Financing Receivable, Impaired [Line Items]
Number of Modifications | LoansModifications	33	34
Gross Loans (at beginning of period)	$ 2,572	$ 4,010
Gross Loans (at period end)	$ 2,354	$ 3,871
Retail/office
Financing Receivable, Impaired [Line Items]
Number of Modifications | LoansModifications	1
Gross Loans (at beginning of period)	$ 752
Gross Loans (at period end)	$ 510
Land and construction
Financing Receivable, Impaired [Line Items]
Number of Modifications | LoansModifications		3
Gross Loans (at beginning of period)		$ 427
Gross Loans (at period end)		$ 410
Multi-family
Financing Receivable, Impaired [Line Items]
Number of Modifications | LoansModifications		3
Gross Loans (at beginning of period)		$ 1,283
Gross Loans (at period end)		$ 1,183
Other commercial real estate
Financing Receivable, Impaired [Line Items]
Number of Modifications | LoansModifications		2
Gross Loans (at beginning of period)		$ 251
Gross Loans (at period end)		$ 256
Residential
Financing Receivable, Impaired [Line Items]
Number of Modifications | LoansModifications	7	13
Gross Loans (at beginning of period)	$ 549	$ 1,632
Gross Loans (at period end)	$ 582	$ 1,620
Commercial and industrial
Financing Receivable, Impaired [Line Items]
Number of Modifications | LoansModifications	1	2
Gross Loans (at beginning of period)	$ 12	$ 64
Gross Loans (at period end)	$ 11	$ 97
Consumer loans | Other consumer
Financing Receivable, Impaired [Line Items]
Number of Modifications | LoansModifications	24	11
Gross Loans (at beginning of period)	$ 1,259	$ 353
Gross Loans (at period end)	$ 1,251	$ 305