Segment Information (Reconciliation of Segment Income from Operations to Consolidated Income Before Income Taxes) (Details) - USD ($) $ in Thousands	3 Months Ended								6 Months Ended	12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting [Abstract]
Adjusted EBITDA										$ 250,117	$ 280,143	$ 252,146
Depreciation, depletion and amortization										(379,345)	(418,748)	(426,442)
Amortization of acquired sales contracts, net										8,811	13,187	9,457
Asset impairment costs	$ (488,865)	$ (2,120,292)	$ (19,146)	$ 0	$ (17,541)	$ (5,060)	$ (1,512)	$ 0	$ (2,600,000)	(2,628,303)	(24,113)	(220,879)
Goodwill impairment										0	0	(265,423)
Losses from disposed operations resulting from Patriot Coal bankruptcy										(116,343)	0	0
Settlement of UMWA legal claims										0	0	(12,000)
Interest expense, net										(393,549)	(383,188)	(374,664)
Nonoperating expense										(27,910)	0	(42,921)
Loss from continuing operations before income taxes										$ (3,286,522)	$ (532,719)	$ (1,080,726)