Income Taxes (Reconciliation of Income Tax Expense Based on Federal Statutory Rate) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Income Tax Disclosure [Abstract]
Income before income taxes	$ 7,467,808	$ 6,130,718	$ 12,716,331	$ 9,267,093
Corporate federal tax rate	21.00%	21.00%	21.00%	21.00%
Income tax expense computed at the federal statutory rate	$ 1,568,240	$ 1,287,451	$ 2,670,430	$ 1,946,090
State income taxes, net of federal tax benefit	338,631	290,481	588,668	441,070
Net amortization of excess deferred taxes on regulated operations	(86,208)	(86,208)	(124,332)	(172,417)
Other, net	(33,171)	(31,096)	(105,687)	(51,902)
Total income tax expense	$ 1,787,492	$ 1,460,628	$ 3,029,079	$ 2,162,841
Effective tax rate	23.90%	23.80%	23.80%	23.30%