Income Taxes (Schedule of Deferred Tax Assets and Liabilities) (Details) - USD ($)	Sep. 30, 2020	Sep. 30, 2019
Deferred tax assets:
Allowance for uncollectibles	$ 180,986	$ 28,503
Accrued pension and postretirement medical benefits	651,356	782,592
Regulatory effect of change in federal income tax rate	2,814,525	2,867,383
Accrued vacation	140,635	150,882
Over-recovery of gas costs	0	23,979
Cost of gas held in storage	604,962	590,495
Deferred compensation	992,605	803,979
Interest rate swaps	572,343	230,204
Rate refund	0	130,063
Other	97,564	261,125
Total gross deferred tax assets	6,054,976	5,869,205
Deferred tax liabilities:
Utility plant	18,310,474	18,132,022
MVP investment	1,693,075	705,193
Other	25,189	10,513
Total gross deferred tax liabilities	20,028,738	18,847,728
Net deferred tax liability	$ 13,973,762	$ 12,978,523