Note 11 - Other Comprehensive Income (Loss) - Schedule of Other Comprehensive Income and Loss (Details) - USD ($)	3 Months Ended	9 Months Ended
Jun. 30, 2024	Mar. 31, 2024	Dec. 31, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Jun. 30, 2024	Jun. 30, 2023
Unrealized gains (losses)	$ 207,785			$ 1,111,338			$ (174,113)	$ (894,741)
Unrealized gains (losses)	(53,484)			(286,058)			44,816	230,304
Unrealized gains (losses)	154,301			825,280			(129,297)	(664,437)
Transfer of realized gains to interest expense	(476,053)			(490,371)			(1,554,942)	(1,200,862)
Transfer of realized gains to interest expense	122,535			126,221			400,240	309,100
Transfer of realized gains to interest expense	(353,518)			(364,150)			(1,154,702)	(891,762)
Net interest rate swaps	(268,268)			620,967			(1,380,829)	(306,121)
Net interest rate swaps	69,051			(159,837)			355,424	78,796
Net interest rate swaps	(199,217)			461,130			(1,025,405)	(227,325)
Amortization of net actuarial losses	16,015			19,703			48,045	59,109
Amortization of net actuarial losses	(4,122)			(5,072)			(12,366)	(15,216)
Amortization of net actuarial losses	11,893			14,631			35,679	43,893
Other comprehensive loss	(252,253)			640,670			(1,332,784)	(247,012)
Other comprehensive loss	64,929			(164,909)			343,058	63,580
Other comprehensive loss	(187,324)	$ 211,425	$ (1,013,827)	475,761	$ (490,526)	$ (168,667)	(989,726)	(183,432)
Unrealized gains	(207,785)			(1,111,338)			174,113	894,741
Unrealized gains	53,484			286,058			(44,816)	(230,304)
Unrealized gains	$ (154,301)			$ (825,280)			$ 129,297	$ 664,437

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