Accumulated Other Comprehensive Income (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Hedging Derivative Activities
Beginning balance, Hedging Derivative Activities	$ (191,000)	$ (612,000)
Other comprehensive income (loss) before reclassifications, Hedging Derivative Activities	(773,000)	791,000
Amounts reclassified from accumulated other comprehensive income (loss), Hedging Derivative Activities	1,026,000	230,000
Income tax benefit (expense), hedging activities	(62,000)	(140,000)
Ending balance, Hedging Derivative Activities	0	(191,000)	$ (612,000)
Post Retirement Benefit Plan Items
Beginning balance, Post Retirement Benefit Plan Items	1,561,000	2,729,000
Other comprehensive income (loss) before reclassifications, Post Retirement Benefit Plan Items	102,000	(1,102,000)
Amounts reclassified from accumulated other comprehensive income (loss), Post Retirement Benefit Plan Items	315,000	379,000
Income tax benefit (expense), Post retirement benefits	(27,000)	(313,000)	(123,000)
Ending balance, Post Retirement Benefit Plan Items	1,375,000	1,561,000	2,729,000
Accumulated Other Comprehensive Income (Loss)
Beginning balance, Accumulated Other Comprehensive Income (Loss)	1,370,000	2,117,000
Other comprehensive income (loss) before reclassifications, Accumulated Other Comprehensive Income (Loss)	(671,000)	(311,000)
Reclassification from Accumulated Other Comprehensive Income, Current Period, before Tax	711,000	(609,000)
Income tax benefit (expense), Accumulated Other Comprehensive Income (Loss)	35,000	(173,000)
Ending balance, Accumulated Other Comprehensive Income (Loss)	$ 1,375,000	$ 1,370,000	$ 2,117,000