| Schedule of Net Benefit Costs [Table Text Block] |
| | | Three Months Ended June 30, | | | Nine Months Ended June 30, | |
| | | 2026 | | | 2025 | | | 2026 | | | 2025 | |
| Components of net periodic pension cost: | | | | | | | | | | | | | | | | |
| Service cost | | $ | 92,967 | | | $ | 96,858 | | | $ | 278,901 | | | $ | 290,574 | |
| Interest cost | | | 380,324 | | | | 352,602 | | | | 1,140,972 | | | | 1,057,806 | |
| Expected return on plan assets | | | (427,888 | ) | | | (375,976 | ) | | | (1,283,664 | ) | | | (1,127,928 | ) |
| Recognized loss | | | 10,943 | | | | 14,857 | | | | 32,829 | | | | 44,571 | |
| Net periodic pension cost | | $ | 56,346 | | | $ | 88,341 | | | $ | 169,038 | | | $ | 265,023 | |
| | | Three Months Ended June 30, | | | Nine Months Ended June 30, | |
| | | 2026 | | | 2025 | | | 2026 | | | 2025 | |
| Components of postretirement benefit cost: | | | | | | | | | | | | | | | | |
| Service cost | | $ | — | | | $ | 1,095 | | | $ | — | | | $ | 3,285 | |
| Interest cost | | | 130,327 | | | | 126,856 | | | | 390,981 | | | | 380,568 | |
| Expected return on plan assets | | | (216,083 | ) | | | (182,430 | ) | | | (648,249 | ) | | | (547,290 | ) |
| Recognized gain | | | (50,507 | ) | | | (58,153 | ) | | | (151,521 | ) | | | (174,459 | ) |
| Net postretirement benefit cost (income) | | $ | (136,263 | ) | | $ | (112,632 | ) | | $ | (408,789 | ) | | $ | (337,896 | ) |
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