Allowance for Credit Losses and Credit Quality - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Receivables [Abstract]
Commitments to lend additional funds	$ 1,300		$ 1,300		$ 638
Other real estate owned and repossessed and returned assets, write down	$ 1,100	$ 2,300	$ 2,300	$ 5,500