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, 2013	Sep. 30, 2012	Sep. 30, 2011
Income Taxes [Abstract]
Provision (benefit) for income taxes at statutory rate	$ 7,241,517	$ 3,725,749	$ 4,090,069
Percentage depletion	(1,059,303)	(846,040)	(733,516)
State income taxes, net of federal provision (benefit)	572,650	464,677	(92,989)
State net operating loss valuation allowance (release)		(31,000)	31,000
Other	(24,864)	(39,386)	(102,564)
provision (benefit) for income taxes	$ 6,730,000	$ 3,274,000	$ 3,192,000