Consolidated Statements of Comprehensive Income (Parentheticals) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Statement Of Income And Comprehensive Income [Abstract]
Net gain (loss) arising during the period, tax expense (benefit)	$ 11,444	$ (3,531)	$ (1,348)
Effect of pension settlement, tax benefit	0	11,177	0
Amortization of actuarial loss included in net income, tax expense	4,901	4,445	3,772
Amortization of prior service credit included in net income, tax benefit	(288)	(303)	(2,244)
Cash flow hedge, tax expense (benefit)	$ 1,706	$ 396	$ (978)

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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- Definition

Amount of tax expense (benefit) for increase (decrease) to other comprehensive income from settlement and curtailment gain (loss) of defined benefit plan.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=124509347&loc=d3e640-108580

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 45
-Paragraph 19
-URI http://asc.fasb.org/extlink&oid=123454820&loc=SL4569616-111683

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- Definition

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

+ References

+ Details

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- Definition

Amount, before reclassification, of tax expense (benefit) for gain (loss) from derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=124509347&loc=d3e640-108580

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

+ References

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