Employee Benefit Plans, Restricted Stock Plan (Details) - Restricted Stock [Member] - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Deferred Compensation Arrangements [Abstract]
Number of shares authorized (in shares)	150,000
Number of shares available for grant (in shares)	123,966
Unvested Shares [Roll Forward]
Outstanding, beginning of period (in shares)	10,202
Granted (in shares)	88
Forfeited (in shares)	(60)
Vested (in shares)	(32)
Outstanding, end of period (in shares)	10,198
Weighted Average Market Price [Roll Forward]
Outstanding, beginning of period (in dollars per share)	$ 55.93
Granted (in dollars per share)	56.81
Forfeited (in dollars per share)	(54.07)
Vested (in dollars per share)	(58.24)
Outstanding, end of period (in dollars per share)	$ 55.94
Additional General Disclosures [Abstract]
Share-based compensation expense	$ 84,000	$ 82,000
Compensation cost related to nonvested awards that has not yet been recognized	$ 570,000
Period over which compensation cost is expected to be recognized	3 years