Business Combinations - Due Diligence, Merger-related and Merger Integration Costs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Business Combinations [Abstract]
Advertising	$ 0	$ 89	$ 61	$ 108
Employee Benefits	0	5	271	10
Occupancy and bank premises	0	0	2,145	0
Furniture, fixtures, and equipment	0	31	365	37
Information technology	167	41	421	300
Professional fees	193	632	1,450	1,570
Salaries and wages	29	28	852	428
Other	0	24	2,196	144
Total due diligence, merger-related and merger integration expenses	$ 389	$ 850	$ 7,761	$ 2,597