Employee Benefit Plans, Restricted Stock Plan (Details) - Restricted Stock [Member] - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Deferred Compensation Arrangements [Abstract]
Number of shares authorized (in shares)	150,000		150,000
Number of shares available for grant (in shares)	120,432		120,432
Unvested Shares [Roll Forward]
Outstanding, beginning of period (in shares)	10,198		10,202
Granted (in shares)	3,531		3,619
Forfeited (in shares)	0		(60)
Vested (in shares)	(7,107)		(7,139)
Outstanding, end of period (in shares)	6,622		6,622
Weighted Average Market Price [Roll Forward]
Outstanding, beginning of period (in dollars per share)	$ 55.94		$ 55.93
Granted (in dollars per share)	60.30		60.21
Forfeited (in dollars per share)	0		(54.07)
Vested (in dollars per share)	(56.43)		(56.44)
Outstanding, end of period (in dollars per share)	$ 57.74		$ 57.74
Additional General Disclosures [Abstract]
Share-based compensation expense	$ 76,000	$ 83,000	$ 160,000	$ 165,000
Compensation cost related to nonvested awards that has not yet been recognized	$ 382,000		$ 382,000
Period over which compensation cost is expected to be recognized			3 years