Note 10 - Benefit Plans - Assumptions Used to Determine Benefit Obligations and Net Periodic Benefit (Details)	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021
Benefit obligations, discount rate	4.93%	2.59%
Benefit obligations, salary scale	3.00%
Benefit cost, long term rate of return	2.59%
Benefit cost, salary scale	3.00%
Supplemental Employee Retirement Plan [Member]
Benefit obligations, discount rate		3.00%
Benefit cost, discount rate		2.36%
Benefit cost, salary scale		3.00%
Pension Plan [Member] \| Corporate Segment [Member]
Benefit cost, discount rate		2.36%
Benefit cost, long term rate of return		8.00%
Pension Plan [Member] \| Plants [Member]
Benefit cost, discount rate		2.21%
Benefit cost, long term rate of return		8.00%

Weighted average rate for present value of future retirement benefits cash flows, used to determine benefit obligation of defined benefit plan.

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- Definition

Weighted average rate increase of compensation, used to determine benefit obligation of defined benefit plan. Plan includes, but is not limited to, pay-related defined benefit plan.

+ References

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- Definition

Weighted average rate for present value of future retirement benefits cash flows, used to determine net periodic benefit cost of defined benefit plan.

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- Definition

Weighted average rate of return on plan assets, reflecting average rate of earnings expected on existing plan assets and expected contributions, used to determine net periodic benefit cost of defined benefit 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 (k)(3)
-URI https://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 50
-Paragraph 8
-URI https://asc.fasb.org/extlink&oid=123447040&loc=d3e2919-114920

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Weighted average rate of compensation increase used to determine net periodic benefit cost of defined benefit plan. Plan includes, but is not limited to, pay-related defined benefit plan.

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