Note 9 - Employee Benefit Plans - Expected Future Benefit Payments (Details)	Sep. 30, 2023 USD ($)
Pension Plan [Member]
2024	$ 1,335,133
2025	1,400,453
2026	1,486,089
2027	1,591,928
2028	1,665,580
2029 - 2033	9,316,587
Other Postretirement Benefits Plan [Member]
2024	713,518
2025	707,987
2026	710,935
2027	724,277
2028	721,402
2029 - 2033	$ 3,957,815

Amount of benefit for defined benefit plan expected to be paid in five fiscal years after fifth fiscal year following current fiscal year.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (f)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

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Amount of benefit for defined benefit plan expected to be paid in next fiscal year following current fiscal year.

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Amount of benefit for defined benefit plan expected to be paid in second fiscal year following current fiscal year.

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