Loans Held for Investment (Details 4) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014 item	Dec. 31, 2013	Jun. 30, 2013
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	$ 1,466,350	$ 1,243,252	$ 1,059,957
Business loans: Commercial and industrial
Credit Risk Grades
Total Gross Loans	319,541	187,035	146,240
Business loans: Commercial owner occupied
Credit Risk Grades
Total Gross Loans	216,784	221,089	201,802
Business loans: SBA
Credit Risk Grades
Total Gross Loans	15,115	10,659	5,820
Business loans: Warehouse facilities
Credit Risk Grades
Total Gross Loans	114,032	87,517	135,317
Real estate loans: Commercial non-owner occupied
Credit Risk Grades
Total Gross Loans	360,288	333,544	295,767
Real estate loans: Multi-family
Credit Risk Grades
Total Gross Loans	251,512	233,689	172,797
Real estate loans: One-to-four family
Credit Risk Grades
Total Gross Loans	132,020	145,235	84,672
Real estate loans: Construction
Credit Risk Grades
Total Gross Loans	47,034	13,040	2,135
Real estate loans: Land
Credit Risk Grades
Total Gross Loans	6,271	7,605	10,438
Other loans
Credit Risk Grades
Total Gross Loans	3,753	3,839	4,969
Pass
Credit Risk Grades
Total Gross Loans	1,448,510	1,221,125	1,031,298
Pass | Business loans: Commercial and industrial
Credit Risk Grades
Total Gross Loans	317,713	184,247	143,034
Pass | Business loans: Commercial owner occupied
Credit Risk Grades
Total Gross Loans	206,890	207,872	186,271
Pass | Business loans: SBA
Credit Risk Grades
Total Gross Loans	15,115	10,659	5,820
Pass | Business loans: Warehouse facilities
Credit Risk Grades
Total Gross Loans	114,032	87,517	135,317
Pass | Real estate loans: Commercial non-owner occupied
Credit Risk Grades
Total Gross Loans	355,878	329,538	289,210
Pass | Real estate loans: Multi-family
Credit Risk Grades
Total Gross Loans	250,494	232,661	170,726
Pass | Real estate loans: One-to-four family
Credit Risk Grades
Total Gross Loans	131,330	144,152	83,395
Pass | Real estate loans: Construction
Credit Risk Grades
Total Gross Loans	47,034	13,040	2,135
Pass | Real estate loans: Land
Credit Risk Grades
Total Gross Loans	6,271	7,605	10,430
Pass | Other loans
Credit Risk Grades
Total Gross Loans	3,753	3,834	4,960
Special Mention
Credit Risk Grades
Total Gross Loans	899	2,092	3,257
Special Mention | Business loans: Commercial and industrial
Credit Risk Grades
Total Gross Loans		12	88
Special Mention | Business loans: Commercial owner occupied
Credit Risk Grades
Total Gross Loans	393	1,217	2,298
Special Mention | Real estate loans: Commercial non-owner occupied
Credit Risk Grades
Total Gross Loans		352	356
Special Mention | Real estate loans: Multi-family
Credit Risk Grades
Total Gross Loans	506	511	515
Substandard
Credit Risk Grades
Total Gross Loans	16,941	20,035	25,402
Substandard | Business loans: Commercial and industrial
Credit Risk Grades
Total Gross Loans	1,828	2,776	3,118
Substandard | Business loans: Commercial owner occupied
Credit Risk Grades
Total Gross Loans	9,501	12,000	13,233
Substandard | Real estate loans: Commercial non-owner occupied
Credit Risk Grades
Total Gross Loans	4,410	3,654	6,201
Substandard | Real estate loans: Multi-family
Credit Risk Grades
Total Gross Loans	512	517	1,556
Substandard | Real estate loans: One-to-four family
Credit Risk Grades
Total Gross Loans	690	1,083	1,277
Substandard | Real estate loans: Land
Credit Risk Grades
Total Gross Loans			8
Substandard | Other loans
Credit Risk Grades
Total Gross Loans		$ 5	$ 9