Noninterest Expense (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Noninterest Expense
Salaries and employee benefits									$ 37,029	$ 34,660	$ 35,146
Occupancy and equipment									4,578	4,378	4,300
Professional fees									2,982	3,471	1,828
Software subscriptions									1,831	1,573	1,214
Insurance expense									1,529	1,275	1,127
Data processing									1,483	1,331	1,371
Amortization of intangible assets									1,361	1,568	1,043
FDIC deposit insurance premiums									1,084	1,160	1,092
Acquisition and integration related costs									671		3,546
Foreclosed assets									6	25	(94)
Other									8,184	8,198	8,100
Total noninterest expense	$ 15,322	$ 14,834	$ 15,254	$ 15,328	$ 14,277	$ 14,296	$ 14,381	$ 14,685	$ 60,738	$ 57,639	58,673
Pre-tax severance and retention cost											$ 2,887