Dispositions (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended	3 Months Ended					12 Months Ended		3 Months Ended		12 Months Ended	3 Months Ended	12 Months Ended
	Sep. 30, 2012	Sep. 30, 2013 Belmont County, Ohio Reserves [Member] T	Sep. 30, 2013 Crowsnest Pass [Member] Rate	Sep. 30, 2013 Potamac Coal Reserves [Member]	Sep. 30, 2013 Robinson Run Longwall Shields [Member] [Member]	Jun. 30, 2012 Burning Star Disposal [Member]	Dec. 31, 2012 Ram River [Member] acre	Dec. 31, 2012 Burning Start No.4 [Member] acre	Sep. 30, 2013 Shoemaker Longwall Shields [Member]	Sep. 30, 2013 Bailey Longwall Shields [Member]	Dec. 31, 2012 Youngs Creek [Member] acre	Jun. 30, 2012 Elk Creek Disposal [Member]	Dec. 31, 2012 Elk Creek [Member] acre
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Tons sold		1,500
Sale Leaseback Transaction, Net Proceeds					$ 68,337				$ 63,839	$ 71,166
Coal Lands and or Surface Rights							36,000	4,300			200,000,000		20,000
Proceeds from Sale of Property, Plant, and Equipment	583,942	2,300	24,764	25,000		13,023	51,869				169,500	26,000
Increase (Decrease) of Restricted Investments			12,263
Disposal Group, Including Discontinued Operation, Assets of Disposal Group											.5
Gain (Loss) on Disposition of Assets		2,300	15,260	24,663		11,261	89,943				150,677	11,235
Interest in Property Sold			50.00%
Gain (Loss) on Sale of Property Plant Equipment					(236)				279	358
royalty percentage retained		.03									.08
Note Receivable 1 year - PPE Sale							25,500
Note Receivable 2 year - PPE Sale							24,500
Restricted Cash and Cash Equivalents							48,294
Transaction and Financing Fees							$ 637