Loans Held for Investment (Details 5) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013 item	Dec. 31, 2012	Sep. 30, 2012
Loans Held for Investment
Number of areas where the entity's credit quality is maintained and credit risk managed	2
Number of Pass scale grades	6
Credit Risk Grades
Total Gross Loans	$ 1,142,015	$ 986,194	$ 864,838
Business loans: Commercial and industrial
Credit Risk Grades
Total Gross Loans	173,720	115,354	88,105
Business loans: Commercial owner occupied
Credit Risk Grades
Total Gross Loans	222,162	150,934	148,139
Business loans: SBA
Credit Risk Grades
Total Gross Loans	6,455	6,882	4,736
Business loans: Warehouse facilities
Credit Risk Grades
Total Gross Loans	49,104	195,761	112,053
Real estate loans: Commercial non-owner occupied
Credit Risk Grades
Total Gross Loans	304,979	253,409	262,046
Real estate loans: Multi-family
Credit Risk Grades
Total Gross Loans	218,929	156,424	173,484
Real estate loans: One-to-four family
Credit Risk Grades
Total Gross Loans	152,667	97,463	62,771
Real estate loans: Construction
Credit Risk Grades
Total Gross Loans	2,835		308
Real estate loans: Land
Credit Risk Grades
Total Gross Loans	7,371	8,774	11,005
Other loans
Credit Risk Grades
Total Gross Loans	3,793	1,193	2,191
Pass
Credit Risk Grades
Total Gross Loans	1,117,312	940,393	835,247
Pass | Business loans: Commercial and industrial
Credit Risk Grades
Total Gross Loans	170,840	111,895	86,000
Pass | Business loans: Commercial owner occupied
Credit Risk Grades
Total Gross Loans	207,519	136,330	137,289
Pass | Business loans: SBA
Credit Risk Grades
Total Gross Loans	6,455	6,819	4,455
Pass | Business loans: Warehouse facilities
Credit Risk Grades
Total Gross Loans	49,104	195,761	112,053
Pass | Real estate loans: Commercial non-owner occupied
Credit Risk Grades
Total Gross Loans	299,940	240,585	252,216
Pass | Real estate loans: Multi-family
Credit Risk Grades
Total Gross Loans	217,897	143,003	170,365
Pass | Real estate loans: One-to-four family
Credit Risk Grades
Total Gross Loans	151,564	96,061	61,378
Pass | Real estate loans: Construction
Credit Risk Grades
Total Gross Loans	2,835		308
Pass | Real estate loans: Land
Credit Risk Grades
Total Gross Loans	7,371	8,762	9,009
Pass | Other loans
Credit Risk Grades
Total Gross Loans	3,787	1,177	2,174
Special Mention
Credit Risk Grades
Total Gross Loans	3,568	15,036	4,844
Special Mention | Business loans: Commercial and industrial
Credit Risk Grades
Total Gross Loans	68	92	847
Special Mention | Business loans: Commercial owner occupied
Credit Risk Grades
Total Gross Loans	2,632	2,674	3,334
Special Mention | Real estate loans: Commercial non-owner occupied
Credit Risk Grades
Total Gross Loans	355	687	663
Special Mention | Real estate loans: Multi-family
Credit Risk Grades
Total Gross Loans	513	11,583
Substandard
Credit Risk Grades
Total Gross Loans	21,135	30,765	24,747
Substandard | Business loans: Commercial and industrial
Credit Risk Grades
Total Gross Loans	2,812	3,367	1,258
Substandard | Business loans: Commercial owner occupied
Credit Risk Grades
Total Gross Loans	12,011	11,930	7,516
Substandard | Business loans: SBA
Credit Risk Grades
Total Gross Loans		63	281
Substandard | Real estate loans: Commercial non-owner occupied
Credit Risk Grades
Total Gross Loans	4,684	12,137	9,167
Substandard | Real estate loans: Multi-family
Credit Risk Grades
Total Gross Loans	519	1,838	3,119
Substandard | Real estate loans: One-to-four family
Credit Risk Grades
Total Gross Loans	1,103	1,402	1,393
Substandard | Real estate loans: Land
Credit Risk Grades
Total Gross Loans		12	1,996
Substandard | Other loans
Credit Risk Grades
Total Gross Loans	$ 6	$ 16	$ 17