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Represents the number of reclamation obligations related to discontinued operations for which the entity remains contingently liable.

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Amount classified as assets attributable to disposal group held for sale or disposed of, expected to be disposed of within one year or the normal operating cycle, if longer.

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Amount before tax of gain (loss) not previously recognized resulting from the disposal of a discontinued operation.

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Amount before tax of income (loss) from a discontinued operation. Includes, but is not limited to, the income (loss) from operations during the phase-out period, gain (loss) on disposal, gain (loss) for reversal of write-down (write-down) to fair value, less cost to sell, and adjustments to a prior period gain (loss) on disposal.

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Amount of tax expense (benefit) related to a discontinued operation. Includes, but is not limited to, tax expense (benefit) related to income (loss) from operations during the phase-out period, tax expense (benefit) related to gain (loss) on disposal, tax expense (benefit) related to gain (loss) for reversal of write-down (write-down) to fair value, less cost to sell, and tax expense (benefit) related to adjustments of a prior period gain (loss) on disposal.

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Amount of revenue attributable to disposal group, including, but not limited to, discontinued operation.

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Amount after tax of income (loss) from a discontinued operation including the portion attributable to the noncontrolling interest. Includes, but is not limited to, the income (loss) from operations during the phase-out period, gain (loss) on disposal, gain (loss) for reversal of write-down (write-down) to fair value, less cost to sell, and adjustments to a prior period gain (loss) on disposal.

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Discontinued Operations (Details) $ in Thousands	3 Months Ended		6 Months Ended
Discontinued Operations (Details) $ in Thousands	Mar. 31, 2016 USD ($)	Mar. 31, 2015 USD ($)	Mar. 31, 2016 USD ($) item	Mar. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Sep. 30, 2013 USD ($)
Discontinued operations
Revenue	$ 0	$ 0	$ 0	$ 0
Gain (loss) from operations of discontinued operations before income taxes	2,679	(14)	2,341	(36)
Loss on disposal	(3,032)	(196)	(3,040)	(241)
Income tax benefit	125	0	255	0
Loss from discontinued operations, net of income taxes	(228)	$ (210)	$ (444)	$ (277)
Coal Cleaning Business \| Discontinued Operations, Disposed of by Sale
Discontinued operations
Remaining assets held for sale						$ 0
Number of sales transactions in which the buyer agreed to assume the lease and certain reclamation obligations \| item			1
Number of reclamation obligations \| item			1
Accrued liability for reclamation obligations	$ 9,800		$ 9,800		$ 7,400