Consolidated Statements of Comprehensive Income (Parentheticals) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
(Tax) benefit on benefit plan liability adjustments - net gain (loss)	$ (1,505)	$ (664)	$ 191
(Tax) benefit on reclassification adjustment of benefit plan liability - net loss	(226)	(665)	(958)
(Tax) benefit on reclassification adjustment of benefit plan liability - prior service cost	28	27	23
Interest Rate Swap
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification,Tax (Benefit)	(721)	(677)	(287)
Commodity Contract
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification,Tax (Benefit)	663	502	(96)
(Tax) benefit on net unrealized gains (losses) on commodity derivatives	$ 193	$ (980)	$ 14