Consolidated Statements of Comprehensive Income (Parentheticals) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
(Tax) benefit on benefit plan liability adjustments - net gain (loss)	$ (664)	$ 191	$ 1,886
(Tax) benefit on benefit plan liability adjustments - prior service costs	0	0	2
(Tax) benefit on reclassification adjustment of benefit plan liability - net loss	(665)	(958)	434
(Tax) benefit on reclassification adjustment of benefit plan liability - prior service cost	27	23	19
Interest Rate Swap
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification,Tax (Benefit)	(677)	(287)	(666)
Commodity Contract
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification,Tax (Benefit)	502	(96)	55
(Tax) benefit on net unrealized gains (losses) on commodity derivatives	$ (980)	$ 14	$ 126

Amount of tax expense (benefit) for (increase) decrease in value of benefit obligation for change in actuarial assumptions and increase (decrease) in value of plan assets from experience different from that assumed of defined benefit plan, that has not been recognized in net periodic benefit (cost) credit.

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Amount of tax (expense) benefit of reclassification adjustment from accumulated other comprehensive (income) loss for prior service cost (credit) of defined benefit plan.

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Amount of tax expense (benefit) for reclassification of gain (loss) from accumulated other comprehensive income (AOCI) for derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

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Amount of tax expense (benefit) for adjustments from accumulated other comprehensive income (AOCI) for gain (loss) from increase (decrease) in value of excluded component of derivative designated and qualifying as hedge. Adjustments include, but are not limited to, reclassifications for sale and settlement, and amounts recognized under systematic and rational method.

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Amount of tax (expense) benefit for cost (credit) of benefit change attributable to participants' prior service from plan amendment or plan initiation of defined benefit plan, that has not been recognized in net periodic benefit cost (credit).

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Amount of tax (expense) benefit for reclassification adjustment from accumulated other comprehensive (income) loss of defined benefit plan.

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