Loans Held for Investment, net - Risk Category of Loans by Class of Loans (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	$ 1,640,853	$ 1,573,020	$ 1,621,554
Total gross loans	66,980	93,498	95,451
Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	25,199	16,514	21,591
Total gross loans	79	954	992
Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	766,925	683,509	702,355
Land and construction
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	7,432	16,632	19,973
Land and construction | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	143,419	106,436
Multi-family
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	24,416	28,444	11,456
Multi-family | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	318,313	265,735
Retail/office
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	11,848	16,247	25,988
Retail/office | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	161,497	155,095
Other commercial real estate | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	143,696	156,243
Total gross loans	$ 9,214	$ 15,471	$ 14,821
Pass
Financing Receivable, Recorded Investment [Line Items]
Percent of total gross loans	96.60%	93.00%
Pass | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	$ 24,364	$ 14,990
Pass | Total
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	765,497	650,924
Pass | Land and construction | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	137,383	85,425
Pass | Multi-family | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	315,366	261,254
Pass | Retail/office | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	156,737	143,260
Pass | Other commercial real estate | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	$ 131,647	$ 145,995
Special mention
Financing Receivable, Recorded Investment [Line Items]
Percent of total gross loans	0.00%	0.80%
Special mention | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	$ 0	$ 0
Special mention | Total
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	274	5,873
Special mention | Land and construction | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	0	946
Special mention | Multi-family | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	0	0
Special mention | Retail/office | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	274	4,753
Special mention | Other commercial real estate | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	$ 0	$ 174
Substandard
Financing Receivable, Recorded Investment [Line Items]
Percent of total gross loans	2.20%	2.10%
Substandard | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	$ 674	$ 1,491
Substandard | Total
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	17,026	14,840
Substandard | Land and construction | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	579	2,870
Substandard | Multi-family | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	1,749	915
Substandard | Retail/office | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	3,121	3,112
Substandard | Other commercial real estate | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	$ 10,903	$ 6,452
Non-accrual
Financing Receivable, Recorded Investment [Line Items]
Percent of total gross loans	1.20%	4.10%
Non-Accrual	$ 9,327	$ 28,386
Total gross loans	15,309	35,115
Non-accrual | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Non-Accrual	161	33
Non-accrual | Land and construction | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Non-Accrual	5,457	17,195
Non-accrual | Multi-family | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Non-Accrual	1,198	3,566
Non-accrual | Retail/office | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Non-Accrual	1,365	3,970
Non-accrual | Other commercial real estate | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Non-Accrual	$ 1,146	$ 3,622
Total Gross Loans
Financing Receivable, Recorded Investment [Line Items]
Percent of total gross loans	100.00%	100.00%
Total Gross Loans | Commercial and industrial
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	$ 25,199	$ 16,514
Total Gross Loans | Total
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	792,124	700,023
Total Gross Loans | Land and construction | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	143,419	106,436
Total Gross Loans | Multi-family | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	318,313	265,735
Total Gross Loans | Retail/office | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	161,497	155,095
Total Gross Loans | Other commercial real estate | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total gross loans	$ 143,696	$ 156,243