Employee Benefit Plans, Restricted Stock Plan (Details) - Restricted Stock [Member] - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Deferred Compensation Arrangements [Abstract]
Number of shares authorized (in shares)	150,000		150,000
Number of shares available for grant (in shares)	124,479		124,479
Unvested Shares [Roll Forward]
Outstanding, beginning of period (in shares)	10,786		10,877
Granted (in shares)	85		4,732
Forfeited (in shares)	0		0
Vested (in shares)	0		(4,738)
Outstanding, end of period (in shares)	10,871		10,871
Weighted Average Market Price [Roll Forward]
Outstanding, beginning of period (in dollars per share)	$ 56.60		$ 60.11
Granted (in dollars per share)	58.37		51.29
Forfeited (in dollars per share)	0		0
Vested (in dollars per share)	0		(59.32)
Outstanding, end of period (in dollars per share)	$ 56.61		$ 56.61
Additional General Disclosures [Abstract]
Share-based compensation expense	$ 83,000	$ 78,000	$ 248,000	$ 219,000
Compensation cost related to nonvested awards that has not yet been recognized	$ 615,000		$ 615,000
Period over which compensation cost is expected to be recognized			3 years