Investment Securities - Total Gross Proceeds from Sales of Securities (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Available for sale (AFS):
Available-for-sale securities, gross realized gains	$ 1,013	$ 190	$ 1,220	$ 208
Available-for-sale securities, gross realized losses	0	1	0	8
Mortgage-backed securities
Available for sale (AFS):
Available-for-sale securities, gross realized gains	0	0	83	0
State and political securities
Available for sale (AFS):
Available-for-sale securities, gross realized gains	839	190	943	204
Available-for-sale securities, gross realized losses	0	1	0	3
Other debt securities
Available for sale (AFS):
Available-for-sale securities, gross realized gains	174	0	194	4
Available-for-sale securities, gross realized losses	$ 0	$ 0	$ 0	$ 5