CWP and Workers Comp - Net Periodic Costs (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Schedule of Net Periodic Benefit Costs and Assumptions for Defined Benefit Postretirement Plans [Line Items]
Amortization of actuarial gain	$ 10,861	$ 23,559	$ 21,507	$ 48,747
Net periodic (benefit) cost	29,026	20,435	37,130	64,526
Coal Workers Pneumoconiosis [Member]
Schedule of Net Periodic Benefit Costs and Assumptions for Defined Benefit Postretirement Plans [Line Items]
Service cost	1,418	2,135	2,837	4,270
Interest cost	1,385	1,808	2,769	3,616
Amortization of actuarial gain	(1,549)	(4,212)	(3,098)	(8,425)
State administrative fees and insurance bond premiums	0	0	0	0
Legal and administrative costs	0	0	0	0
Net periodic (benefit) cost	1,254	(269)	2,508	(539)
Payments for Coal Workers Pnenumoconiosis			6,062
Workers Compensation [Member]
Schedule of Net Periodic Benefit Costs and Assumptions for Defined Benefit Postretirement Plans [Line Items]
Service cost	2,445	3,533	4,890	7,066
Interest cost	895	1,655	1,789	3,310
Amortization of actuarial gain	(96)	(699)	(191)	(1,398)
State administrative fees and insurance bond premiums	929	1,345	2,039	3,004
Legal and administrative costs	0	591	0	1,182
Net periodic (benefit) cost	4,173	6,425	8,527	13,164
Payments for workers compensation benefits, state administrative fees and surety bond premiums			6,914
Discontinued Operations [Member] | Coal Workers Pneumoconiosis [Member]
Schedule of Net Periodic Benefit Costs and Assumptions for Defined Benefit Postretirement Plans [Line Items]
Net periodic (benefit) cost		(165)		(330)
Discontinued Operations [Member] | Workers Compensation [Member]
Schedule of Net Periodic Benefit Costs and Assumptions for Defined Benefit Postretirement Plans [Line Items]
Net periodic (benefit) cost		$ 2,318		$ 4,853