Retirement Benefit Plans (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2022 USD ($)	Jun. 30, 2021 USD ($)	Jun. 30, 2022 USD ($)	Jun. 30, 2021 USD ($)	Dec. 31, 2021
Net Periodic Benefit Cost [Line Items]
Interest credit under cash balance plan			0.03
Employer matching contribution, percentage			5.00%
Employees' Pension Plan
Net Periodic Benefit Cost [Line Items]
Assumptions used calculating benefit obligation, interest rate to annuitize cash balance account					1.02%
Defined benefit plan, increase in benefit payable, percent	3.00%		3.00%
Defined benefit plan, benefit obligation, increase (decrease) for plan amendment			$ 351,638
Defined benefit plan, amortization of service cost			9 years 8 months 12 days
Service Cost	$ 451,000	$ 507,000	$ 939,000	$ 967,000
Interest Cost	352,000	343,000	719,000	683,000
Expected Return on Plan Assets	(1,058,000)	(940,000)	(2,157,000)	(1,890,000)
Amortization of Prior Service (Credit) Cost	20,000	19,000	39,000	39,000
Amortization of Net Loss (Gain)	0	0	0	0
Net Periodic (Benefit) Cost	(235,000)	(71,000)	(460,000)	(201,000)
Plan Contributions During the Period	0	0	0	0
Estimated Future Contributions in the Current Fiscal Year	0		$ 0
Select Executive Retirement Plan
Net Periodic Benefit Cost [Line Items]
Assumptions used calculating benefit obligation, interest rate to annuitize cash balance account					2.72%
Defined benefit plan, amortization of service cost			12 years 6 months
Defined benefit plan, benefit obligation, period increase (decrease)			$ 122,797
Service Cost	271,000	173,000	418,000	291,000
Interest Cost	61,000	50,000	112,000	95,000
Expected Return on Plan Assets	0	0	0	0
Amortization of Prior Service (Credit) Cost	11,000	12,000	22,000	24,000
Amortization of Net Loss (Gain)	67,000	52,000	106,000	90,000
Net Periodic (Benefit) Cost	410,000	287,000	658,000	500,000
Plan Contributions During the Period	115,000	118,000	231,000	236,000
Estimated Future Contributions in the Current Fiscal Year	230,000		230,000
Post-Retirement Benefit Plans
Net Periodic Benefit Cost [Line Items]
Assumptions used calculating benefit obligation, interest rate to annuitize cash balance account					3.08%
Service Cost	18,000	24,000	45,000	55,000
Interest Cost	60,000	57,000	124,000	124,000
Expected Return on Plan Assets	0	0	0	0
Amortization of Prior Service (Credit) Cost	26,000	26,000	53,000	53,000
Amortization of Net Loss (Gain)	(46,000)	(52,000)	(78,000)	(44,000)
Net Periodic (Benefit) Cost	58,000	55,000	144,000	188,000
Plan Contributions During the Period	33,000	$ 27,000	88,000	$ 55,000
Estimated Future Contributions in the Current Fiscal Year	$ 66,000		$ 66,000
On or Subsequent to January 1, 2003
Net Periodic Benefit Cost [Line Items]
Service credits, percent of eligible salaries			6.00%
Minimum | Prior to January 1, 2003
Net Periodic Benefit Cost [Line Items]
Service credits, percent of eligible salaries			6.00%
Maximum | Prior to January 1, 2003
Net Periodic Benefit Cost [Line Items]
Service credits, percent of eligible salaries			12.00%