Loans Held for Investment (Details 6) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2012
Other information concerning the credit quality
Current	$ 1,140,966	$ 985,303	$ 857,955
30-59 Days Past Due	724	106	2,565
60-89 Days Past Due	214	303	164
90+ Days Past Due	111	482	4,154
Total	1,142,015	986,194	864,838
Non-Accruing	1,153	2,206	6,280
Business loans: Commercial and industrial
Other information concerning the credit quality
Current	173,478	115,078	87,984
30-59 Days Past Due	163
60-89 Days Past Due	79	58	121
90+ Days Past Due		218
Total	173,720	115,354	88,105
Non-Accruing	78	347
Business loans: Commercial owner occupied
Other information concerning the credit quality
Current	222,162	150,689	147,812
30-59 Days Past Due			327
60-89 Days Past Due		245
Total	222,162	150,934	148,139
Non-Accruing		14	218
Business loans: SBA
Other information concerning the credit quality
Current	6,312	6,697	4,551
60-89 Days Past Due	129
90+ Days Past Due	14	185	185
Total	6,455	6,882	4,736
Non-Accruing	142	260	266
Business loans: Warehouse facilities
Other information concerning the credit quality
Current	49,104	195,761	112,053
Total	49,104	195,761	112,053
Real estate loans: Commercial non-owner occupied
Other information concerning the credit quality
Current	304,420	253,409	256,489
30-59 Days Past Due	559		1,708
90+ Days Past Due			3,849
Total	304,979	253,409	262,046
Non-Accruing	437	670	4,528
Real estate loans: Multi-family
Other information concerning the credit quality
Current	218,929	156,424	173,484
Total	218,929	156,424	173,484
Non-Accruing		266	273
Real estate loans: One-to-four family
Other information concerning the credit quality
Current	152,570	97,283	62,307
30-59 Days Past Due		101	301
60-89 Days Past Due			43
90+ Days Past Due	97	79	120
Total	152,667	97,463	62,771
Non-Accruing	496	522	578
Real estate loans: Construction
Other information concerning the credit quality
Current	2,835		308
Total	2,835		308
Real estate loans: Land
Other information concerning the credit quality
Current	7,371	8,774	10,776
30-59 Days Past Due			229
Total	7,371	8,774	11,005
Non-Accruing		127	417
Other loans
Other information concerning the credit quality
Current	3,785	1,188	2,191
30-59 Days Past Due	2	5
60-89 Days Past Due	6
Total	$ 3,793	$ 1,193	$ 2,191