Discontinued Operations (Details) (USD $)	3 Months Ended		6 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2015 item	Mar. 31, 2014	Jan. 31, 2013
Discontinued operations
Income (loss) from discontinued operations, net of income taxes	$ (210,000)	$ (575,000)	$ (277,000)	$ 125,000
Coal Cleaning Business
Discontinued operations
Remaining assets held for sale					0
Revenue	0	0	0	0
Loss from operations of discontinued operations before income taxes	(14,000)	(2,728,000)	(36,000)	(2,992,000)
Gain (loss) on disposal	(196,000)	2,153,000	(241,000)	3,117,000
Income tax provision	0	0	0	0
Income (loss) from discontinued operations, net of income taxes	(210,000)	(575,000)	(277,000)	125,000
Number of sales transactions in which the buyer agreed to assume the lease and certain reclamation obligations			1
Number of reclamation obligations			1
Accrued liability for reclamation obligations	$ 8,000,000		$ 8,000,000