Loans - Days past due and Non-accruing (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Other information concerning the credit quality
Total Gross Loans	$ 3,245,694	$ 2,262,683
Non-accruing	1,141	3,970
Business loans: Commercial and industrial
Other information concerning the credit quality
Total Gross Loans	563,169	309,741
Business loans: Franchise loans
Other information concerning the credit quality
Total Gross Loans	459,421	328,925
Business loans: Commercial owner occupied
Other information concerning the credit quality
Total Gross Loans	454,918	294,726
Business loans: SBA
Other information concerning the credit quality
Total Gross Loans	96,705	62,256
Business loans: Warehouse facilities
Other information concerning the credit quality
Total Gross Loans		143,200
Real estate loans: Commercial non-owner occupied
Other information concerning the credit quality
Total Gross Loans	586,975	421,583
Real estate loans: Multi-family
Other information concerning the credit quality
Total Gross Loans	690,955	429,003
Real estate loans: One-to-four family
Other information concerning the credit quality
Total Gross Loans	100,451	80,050
Real estate loans: Construction
Other information concerning the credit quality
Total Gross Loans	269,159	169,748
Real estate loans: Land
Other information concerning the credit quality
Total Gross Loans	19,829	18,340
Other loans
Other information concerning the credit quality
Total Gross Loans	4,112	5,111
Non-accruing	0	1
Current
Other information concerning the credit quality
Current	3,244,862	2,260,051
Current | Other loans
Other information concerning the credit quality
Current	4,112	5,111
30-59
Other information concerning the credit quality
Days Past Due	122	323
30-59 | Other loans
Other information concerning the credit quality
Days Past Due	0	0
60-89
Other information concerning the credit quality
Days Past Due	71	355
60-89 | Other loans
Other information concerning the credit quality
Days Past Due	0	0
90
Other information concerning the credit quality
Days Past Due	639	1,954
90 | Other loans
Other information concerning the credit quality
Days Past Due	0	0
Commercial Portfolio Segment | Business loans: Commercial and industrial
Other information concerning the credit quality
Total Gross Loans	563,169	309,741
Non-accruing	250	463
Commercial Portfolio Segment | Business loans: Franchise loans
Other information concerning the credit quality
Total Gross Loans	459,421	328,925
Non-accruing	0	1,630
Commercial Portfolio Segment | Business loans: Commercial owner occupied
Other information concerning the credit quality
Total Gross Loans	454,918	294,726
Non-accruing	436	536
Commercial Portfolio Segment | Business loans: SBA
Other information concerning the credit quality
Total Gross Loans	96,705	62,256
Non-accruing	316	0
Commercial Portfolio Segment | Business loans: Warehouse facilities
Other information concerning the credit quality
Total Gross Loans	0	143,200
Non-accruing		0
Commercial Portfolio Segment | Current | Business loans: Commercial and industrial
Other information concerning the credit quality
Current	562,805	309,464
Commercial Portfolio Segment | Current | Business loans: Franchise loans
Other information concerning the credit quality
Current	459,421	327,295
Commercial Portfolio Segment | Current | Business loans: Commercial owner occupied
Other information concerning the credit quality
Current	454,918	294,371
Commercial Portfolio Segment | Current | Business loans: SBA
Other information concerning the credit quality
Current	96,389	62,256
Commercial Portfolio Segment | Current | Business loans: Warehouse facilities
Other information concerning the credit quality
Current		143,200
Commercial Portfolio Segment | 30-59 | Business loans: Commercial and industrial
Other information concerning the credit quality
Days Past Due	104	20
Commercial Portfolio Segment | 30-59 | Business loans: Franchise loans
Other information concerning the credit quality
Days Past Due	0	0
Commercial Portfolio Segment | 30-59 | Business loans: Commercial owner occupied
Other information concerning the credit quality
Days Past Due	0	0
Commercial Portfolio Segment | 30-59 | Business loans: SBA
Other information concerning the credit quality
Days Past Due	0	0
Commercial Portfolio Segment | 30-59 | Business loans: Warehouse facilities
Other information concerning the credit quality
Days Past Due		0
Commercial Portfolio Segment | 60-89 | Business loans: Commercial and industrial
Other information concerning the credit quality
Days Past Due	0	0
Commercial Portfolio Segment | 60-89 | Business loans: Franchise loans
Other information concerning the credit quality
Days Past Due	0	0
Commercial Portfolio Segment | 60-89 | Business loans: Commercial owner occupied
Other information concerning the credit quality
Days Past Due	0	355
Commercial Portfolio Segment | 60-89 | Business loans: SBA
Other information concerning the credit quality
Days Past Due	0	0
Commercial Portfolio Segment | 60-89 | Business loans: Warehouse facilities
Other information concerning the credit quality
Days Past Due		0
Commercial Portfolio Segment | 90 | Business loans: Commercial and industrial
Other information concerning the credit quality
Days Past Due	260	257
Commercial Portfolio Segment | 90 | Business loans: Franchise loans
Other information concerning the credit quality
Days Past Due	0	1,630
Commercial Portfolio Segment | 90 | Business loans: Commercial owner occupied
Other information concerning the credit quality
Days Past Due	0	0
Commercial Portfolio Segment | 90 | Business loans: SBA
Other information concerning the credit quality
Days Past Due	316	0
Commercial Portfolio Segment | 90 | Business loans: Warehouse facilities
Other information concerning the credit quality
Days Past Due		0
Consumer Portfolio Segment | Real estate loans: Commercial non-owner occupied
Other information concerning the credit quality
Total Gross Loans	586,975	421,583
Non-accruing	0	1,164
Consumer Portfolio Segment | Real estate loans: Multi-family
Other information concerning the credit quality
Total Gross Loans	690,955	429,003
Non-accruing	0	0
Consumer Portfolio Segment | Real estate loans: One-to-four family
Other information concerning the credit quality
Total Gross Loans	100,451	80,050
Non-accruing	124	155
Consumer Portfolio Segment | Real estate loans: Construction
Other information concerning the credit quality
Total Gross Loans	269,159	169,748
Non-accruing	0	0
Consumer Portfolio Segment | Real estate loans: Land
Other information concerning the credit quality
Total Gross Loans	19,829	18,340
Non-accruing	15	21
Consumer Portfolio Segment | Current | Real estate loans: Commercial non-owner occupied
Other information concerning the credit quality
Current	586,975	421,369
Consumer Portfolio Segment | Current | Real estate loans: Multi-family
Other information concerning the credit quality
Current	690,955	429,003
Consumer Portfolio Segment | Current | Real estate loans: One-to-four family
Other information concerning the credit quality
Current	100,314	79,915
Consumer Portfolio Segment | Current | Real estate loans: Construction
Other information concerning the credit quality
Current	269,159	169,748
Consumer Portfolio Segment | Current | Real estate loans: Land
Other information concerning the credit quality
Current	19,814	18,319
Consumer Portfolio Segment | 30-59 | Real estate loans: Commercial non-owner occupied
Other information concerning the credit quality
Days Past Due	0	214
Consumer Portfolio Segment | 30-59 | Real estate loans: Multi-family
Other information concerning the credit quality
Days Past Due	0	0
Consumer Portfolio Segment | 30-59 | Real estate loans: One-to-four family
Other information concerning the credit quality
Days Past Due	18	89
Consumer Portfolio Segment | 30-59 | Real estate loans: Construction
Other information concerning the credit quality
Days Past Due	0	0
Consumer Portfolio Segment | 30-59 | Real estate loans: Land
Other information concerning the credit quality
Days Past Due	0	0
Consumer Portfolio Segment | 60-89 | Real estate loans: Commercial non-owner occupied
Other information concerning the credit quality
Days Past Due	0	0
Consumer Portfolio Segment | 60-89 | Real estate loans: Multi-family
Other information concerning the credit quality
Days Past Due	0	0
Consumer Portfolio Segment | 60-89 | Real estate loans: One-to-four family
Other information concerning the credit quality
Days Past Due	71	0
Consumer Portfolio Segment | 60-89 | Real estate loans: Construction
Other information concerning the credit quality
Days Past Due	0	0
Consumer Portfolio Segment | 60-89 | Real estate loans: Land
Other information concerning the credit quality
Days Past Due	0	0
Consumer Portfolio Segment | 90 | Real estate loans: Commercial non-owner occupied
Other information concerning the credit quality
Days Past Due	0	0
Consumer Portfolio Segment | 90 | Real estate loans: Multi-family
Other information concerning the credit quality
Days Past Due	0	0
Consumer Portfolio Segment | 90 | Real estate loans: One-to-four family
Other information concerning the credit quality
Days Past Due	48	46
Consumer Portfolio Segment | 90 | Real estate loans: Construction
Other information concerning the credit quality
Days Past Due	0	0
Consumer Portfolio Segment | 90 | Real estate loans: Land
Other information concerning the credit quality
Days Past Due	$ 15	$ 21