Employee Benefit Plans, Restricted Stock Plan (Details) - Restricted Stock [Member] - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Deferred Compensation Arrangements [Abstract]
Number of shares authorized (in shares)	150,000		150,000
Number of shares available for grant (in shares)	119,637		119,637
Unvested Shares [Roll Forward]
Outstanding, beginning of period (in shares)	6,622		10,202
Granted (in shares)	795		4,414
Forfeited (in shares)	0		(60)
Vested (in shares)	0		(7,139)
Outstanding, end of period (in shares)	7,417		7,417
Weighted Average Market Price [Roll Forward]
Outstanding, beginning of period (in dollars per share)	$ 57.74		$ 55.93
Granted (in dollars per share)	63.12		60.21
Forfeited (in dollars per share)	0		(54.07)
Vested (in dollars per share)	0		(56.44)
Outstanding, end of period (in dollars per share)	$ 58.32		$ 58.32
Additional General Disclosures [Abstract]
Share-based compensation expense	$ 79,000	$ 83,000	$ 239,000	$ 248,000
Compensation cost related to nonvested awards that has not yet been recognized	$ 433,000		$ 433,000
Period over which compensation cost is expected to be recognized			3 years