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Note 9 - Pensions and Other Postretirement Benefits (Details Textual) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement | $ 2,300 | $ 4,600 | $ 0
Unrecognized Actuarial Gain (Loss) in Excess of Benefit Obligation, Percentage | 10.00% |  |
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year | $ 2,000 |  |
One Percentage Point Change in Assumed Rate of Return [Member] |  |  |
Defined Benefit Plan Effect On Pension Expense | $ 700 |  |
One Percentage Point Increase in Discount Rate [Member] |  |  |
Defined Benefit Plan Effect On Pension Expense |  | 1,400 |
One Percentage Point Decrease in Discount Rate [Member] |  |  |
Defined Benefit Plan Effect On Pension Expense |  |  | 1,700
Defined Benefit Plan, Equity Securities [Member] | Minimum [Member] |  |  |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 22.00% |  |
Defined Benefit Plan, Equity Securities [Member] | Maximum [Member] |  |  |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 42.00% |  |
Fixed Income Securities [Member] | Minimum [Member] |  |  |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 50.00% |  |
Fixed Income Securities [Member] | Maximum [Member] |  |  |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 70.00% |  |
Alternative Investments [Member] | Minimum [Member] |  |  |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 3.00% |  |
Alternative Investments [Member] | Maximum [Member] |  |  |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 13.00% |  |
Defined Benefit Plan, Cash and Cash Equivalents [Member] | Minimum [Member] |  |  |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 0.00% |  |
Defined Benefit Plan, Cash and Cash Equivalents [Member] | Maximum [Member] |  |  |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 10.00% |  |
Pension Plan [Member] |  |  |
Defined Contribution Plan, Employer Discretionary Contribution Amount | $ 2,300 | 2,300 | 2,300
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement | $ (2,304) | $ (4,583) | $ (0)
Postretirement Health Coverage [Member] |  |  |
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate | 5.00% |  |

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- Definition Unrecognized Actuarial Gain (Loss) in Excess of Benefit Obligation, Percentage. + References No definition available. + Details
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- Definition Amount of contribution expected to be received by defined benefit plan from employer in next fiscal year following current fiscal year. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (g) -URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 55 -Paragraph 18 -URI http://asc.fasb.org/extlink&oid=123450688&loc=d3e4587-114921 + Details
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- Definition Percentage of target investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 55 -Paragraph 17 -URI http://asc.fasb.org/extlink&oid=123450688&loc=d3e4179-114921 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (d)(i) -URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920 + Details
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- Definition Amount of gain (loss) recognized in net periodic benefit (cost) credit from irrevocable action relieving primary responsibility for benefit obligation and eliminating risk related to obligation and assets used to effect settlement. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (h)(7) -URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 45 -Paragraph 3A -URI http://asc.fasb.org/extlink&oid=123453770&loc=SL108413299-114919 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 6 -Subparagraph (a)(7) -URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e2709-114920 + Details
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- Definition Ultimate trend rate for health care cost for defined benefit postretirement plan. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (l) -URI http://asc.fasb.org/extlink&oid=123447040&loc=d3e1928-114920 + Details
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