Preferred and Common Stock (Details) - USD ($) $ in Thousands	12 Months Ended			216 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2016	Dec. 31, 2001
Common stock
Number of shares available to directors and employees for stock purchase or savings and investment plans (in shares)			700,000		250,000
Number of shares issued under employee savings and investment plan (in shares)	52,819
Number of shares available for future use under employee savings and investment plan (in shares)	197,181
Number of shares issued during period, employee benefit plan (in shares)	13,408	12,138	12,762
Number of shares registered with SEC for dividend reinvestment plan (in shares)						600,000
Number of shares issued during period, dividend reinvestment plan (in shares)	11,242	9,524	9,922	278,526
Number of shares for future use (in shares)	321,474
Proceeds from sale of common stock	$ 653	$ 619	$ 632
Capital Purchase Program
Common stock
Proceeds from sale of common stock	$ 653	$ 619	$ 632