Business Combinations - Due Diligence, Merger-related and Merger Integration Costs (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Business Combinations [Abstract]
Advertising	$ 0	$ 2	$ 0	$ 61
Employee benefits	0	68	0	271
Occupancy and bank premises	0	289	0	2,145
Furniture, fixtures, and equipment	0	186	0	365
Data processing	0	142	0	254
Professional fees	0	510	0	1,257
Salaries and wages	0	477	0	823
Other	0	1,378	0	2,195
Total due diligence, merger-related and merger integration expenses	$ 0	$ 3,052	$ 0	$ 7,371