Parent Company Only Financial Statements Condensed balance sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Condensed Financial Statements, Captions [Line Items]
Premises and equipment, net	$ 38,266	$ 40,292
Other assets	18,976	25,904
Total assets	2,841,539	2,884,535
Other liabilities	8,595	5,603
Total liabilities	2,533,575	2,603,862
Stockholders’ equity	307,964	280,673	$ 205,009	$ 164,916
Total liabilities and stockholders’ equity	2,841,539	2,884,535
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Cash	8,296	2,382
Premises and equipment, net	2,654	2,648
Investment in subsidiaries	328,830	315,752
Other assets	3,555	2,982
Total assets	343,335	323,764
Debt	34,313	41,979
Other liabilities	1,058	1,112
Total liabilities	35,371	43,091
Stockholders’ equity	307,964	280,673
Total liabilities and stockholders’ equity	$ 343,335	$ 323,764