Discontinued Operations (Details) (USD $)	3 Months Ended		6 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2012	Mar. 31, 2011	Sep. 30, 2011
Discontinued operations
Loss from discontinued operations, net of income taxes	$ (2,330,000)	$ (42,282,000)	$ (12,798,000)	$ (44,211,000)
Coal cleaning business
Discontinued operations
Revenue	4,507,000	12,094,000	9,798,000	30,360,000
Loss from discontinued operations before income taxes	(2,330,000)	(41,762,000)	(12,798,000)	(43,931,000)
Income tax benefit (provision)	0	(520,000)	0	(280,000)
Loss from discontinued operations, net of income taxes	(2,330,000)	(42,282,000)	(12,798,000)	(44,211,000)
Impairment of coal cleaning assets held for sale		37,000,000		37,000,000
Property, plant and equipment, held for sale	17,000,000		17,000,000		16,100,000
Other non-current assets held for sale	$ 8,400,000		$ 8,400,000		$ 8,300,000