Income Taxes (Summary of Difference Between Provision (Benefit) for Income Taxes and Amount which Would Result from Application of Federal Statutory Rate) (Details) - USD ($)		12 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Income Tax Disclosure [Abstract]
Provision (benefit) for income taxes at statutory rate		$ 465,253	$ 1,477,327	$ (6,299,259)
Percentage depletion		(577,780)	(570,801)	(395,649)
State income taxes, net of federal provision (benefit)		36,980	3,900	(683,800)
Effect of graduated rates			85,644	(86,745)
Restricted stock tax benefit		(69,000)	(238,000)
Deferred directors compensation benefit		(134,000)	(79,000)
Law change	[1]	(12,464,000)
Other		3,547	9,930	(245,547)
Provision (benefit) for income taxes		$ (12,739,000)	$ 689,000	$ (7,711,000)

[1] This is the tax effect of the Tax Cuts and Jobs Act (enacted in December 2017) on our deferred tax liabilities. This Act reduced the U.S. federal corporate tax rate from 35% to 21%.