Securities - Gross Gain (Loss) Realized From the Sale of Securities Available for Sale (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Summary of Significant Accounting Policies.
Gross gains from the sale of securities	$ 1,499	$ 423	$ 105
Gross losses from the sale of securities	(2,200)	(438)	(2,025)
Net losses from the sale of securities	$ (701)	$ (15)	$ (1,920)