Other Comprehensive Income (Reconciliation of Accumulated Comprehensive Income (Loss)) (Details) - USD ($)	3 Months Ended						9 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Jun. 30, 2020	Jun. 30, 2019
Increase (Decrease) in Other Accumulated Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	$ 90,317,347	$ 86,359,135	$ 83,096,392	$ 84,974,517	$ 80,959,740	$ 79,583,112	$ 83,096,392	$ 79,583,112
Other comprehensive income (loss)	(110,009)	(1,199,783)	279,844	(459,812)	(46,034)	(83,316)	(1,029,948)	(589,162)
Balance at end of period	90,251,152	90,317,347	86,359,135	84,736,935	84,974,517	80,959,740	90,251,152	84,736,935
Interest Rate Swaps [Member]
Increase (Decrease) in Other Accumulated Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period			(664,137)				(664,137)
Other comprehensive income (loss)	(126,800)						(1,080,321)
Balance at end of period	(1,744,458)						(1,744,458)
Defined Benefit Plans [Member]
Increase (Decrease) in Other Accumulated Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period			(1,824,780)				(1,824,780)
Other comprehensive income (loss)	16,791			(1,913)			50,373	(5,739)
Balance at end of period	(1,774,407)						(1,774,407)
Accumulated Other Comprehensive Income (Loss) [Member]
Increase (Decrease) in Other Accumulated Comprehensive Income (Loss) [Roll Forward]
Balance at beginning of period	(3,408,856)	(2,209,073)	(2,488,917)	(1,001,018)	(954,984)	(871,668)	(2,488,917)	(871,668)
Other comprehensive income (loss)	(110,009)	(1,199,783)	279,844	(459,812)	(46,034)	(83,316)
Balance at end of period	$ (3,518,865)	$ (3,408,856)	$ (2,209,073)	$ (1,460,830)	$ (1,001,018)	$ (954,984)	$ (3,518,865)	$ (1,460,830)