Delinquencies (Details 6) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014
Other information concerning the credit quality
Total	$ 2,167,547	$ 1,628,445	$ 1,547,911
Non-Accruing	4,095	1,444	1,782
Commercial and industrial
Other information concerning the credit quality
Total	288,982	228,979	218,871
Non-Accruing	237	0	0
Franchise
Other information concerning the credit quality
Total	295,965	199,228	163,887
Non-Accruing	1,630	0	0
Commercial owner occupied
Other information concerning the credit quality
Total	302,556	210,995	215,938
Non-Accruing	556	514	528
SBA
Other information concerning the credit quality
Total	70,191	28,404	20,482
Non-Accruing	0	0	0
Warehouse facilities
Other information concerning the credit quality
Total	144,274	113,798	108,093
Non-Accruing	0	0	0
Commercial non-owner occupied
Other information concerning the credit quality
Total	406,490	359,213	355,984
Non-Accruing	1,424	848	882
Multi-family
Other information concerning the credit quality
Total	421,240	262,965	262,588
Non-Accruing	0	0	0
One-to-four family
Other information concerning the credit quality
Total	78,781	122,795	125,326
Non-Accruing	226	82	372
Construction
Other information concerning the credit quality
Total	141,293	89,682	67,118
Non-Accruing	0	0	0
Land
Other information concerning the credit quality
Total	12,758	9,088	6,103
Non-Accruing	22	0	0
Other loans
Other information concerning the credit quality
Total	5,017	3,298	3,521
Non-Accruing	0	0	0
Current
Other information concerning the credit quality
Current	2,164,606	1,628,347	1,547,505
Current | Commercial and industrial
Other information concerning the credit quality
Current	288,269	228,955	218,871
Current | Franchise
Other information concerning the credit quality
Current	294,335	199,228	163,887
Current | Commercial owner occupied
Other information concerning the credit quality
Current	302,556	210,995	215,938
Current | SBA
Other information concerning the credit quality
Current	70,191	28,404	20,439
Current | Warehouse facilities
Other information concerning the credit quality
Current	144,274	113,798	108,093
Current | Commercial non-owner occupied
Other information concerning the credit quality
Current	406,047	359,213	355,984
Current | Multi-family
Other information concerning the credit quality
Current	421,240	262,965	262,588
Current | One-to-four family
Other information concerning the credit quality
Current	78,648	122,722	124,963
Current | Construction
Other information concerning the credit quality
Current	141,293	89,682	67,118
Current | Land
Other information concerning the credit quality
Current	12,736	9,088	6,103
Current | Other loans
Other information concerning the credit quality
Current	5,017	3,297	3,521
30-59
Other information concerning the credit quality
Days Past Due	702	20	20
30-59 | Commercial and industrial
Other information concerning the credit quality
Days Past Due	681	0	0
30-59 | Franchise
Other information concerning the credit quality
Days Past Due	0	0	0
30-59 | Commercial owner occupied
Other information concerning the credit quality
Days Past Due	0	0	0
30-59 | SBA
Other information concerning the credit quality
Days Past Due	0	0	0
30-59 | Warehouse facilities
Other information concerning the credit quality
Days Past Due	0	0	0
30-59 | Commercial non-owner occupied
Other information concerning the credit quality
Days Past Due	0	0	0
30-59 | Multi-family
Other information concerning the credit quality
Days Past Due	0	0	0
30-59 | One-to-four family
Other information concerning the credit quality
Days Past Due	21	19	20
30-59 | Construction
Other information concerning the credit quality
Days Past Due	0	0	0
30-59 | Land
Other information concerning the credit quality
Days Past Due	0	0	0
30-59 | Other loans
Other information concerning the credit quality
Days Past Due	0	1	0
60-89
Other information concerning the credit quality
Days Past Due	25	24	43
60-89 | Commercial and industrial
Other information concerning the credit quality
Days Past Due	25	24	0
60-89 | Franchise
Other information concerning the credit quality
Days Past Due	0	0	0
60-89 | Commercial owner occupied
Other information concerning the credit quality
Days Past Due	0	0	0
60-89 | SBA
Other information concerning the credit quality
Days Past Due	0	0	43
60-89 | Warehouse facilities
Other information concerning the credit quality
Days Past Due	0	0	0
60-89 | Commercial non-owner occupied
Other information concerning the credit quality
Days Past Due	0	0	0
60-89 | Multi-family
Other information concerning the credit quality
Days Past Due	0	0	0
60-89 | One-to-four family
Other information concerning the credit quality
Days Past Due	0	0	0
60-89 | Construction
Other information concerning the credit quality
Days Past Due	0	0	0
60-89 | Land
Other information concerning the credit quality
Days Past Due	0	0	0
60-89 | Other loans
Other information concerning the credit quality
Days Past Due	0	0	0
90
Other information concerning the credit quality
Days Past Due	2,214	54	343
90 | Commercial and industrial
Other information concerning the credit quality
Days Past Due	7	0	0
90 | Franchise
Other information concerning the credit quality
Days Past Due	1,630	0	0
90 | Commercial owner occupied
Other information concerning the credit quality
Days Past Due	0	0	0
90 | SBA
Other information concerning the credit quality
Days Past Due	0	0	0
90 | Warehouse facilities
Other information concerning the credit quality
Days Past Due	0	0	0
90 | Commercial non-owner occupied
Other information concerning the credit quality
Days Past Due	443	0	0
90 | Multi-family
Other information concerning the credit quality
Days Past Due	0	0	0
90 | One-to-four family
Other information concerning the credit quality
Days Past Due	112	54	343
90 | Construction
Other information concerning the credit quality
Days Past Due	0	0	0
90 | Land
Other information concerning the credit quality
Days Past Due	22	0	0
90 | Other loans
Other information concerning the credit quality
Days Past Due	$ 0	$ 0	$ 0