Business Combinations - Due Diligence, Merger-related and Merger Integration Costs (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Business Combinations [Abstract]
Advertising	$ 61	$ 180	$ 0
Employee Benefits	271	21	0
Occupancy and bank premises	2,145	0	0
Furniture, fixtures, and equipment	365	109	0
Information technology	421	837	0
Professional fees	1,450	3,160	0
Salaries and wages	852	1,285	0
Other	2,196	512	0
Total due diligence, merger-related and merger integration expenses	$ 7,761	$ 6,104	$ 0