CWP and Workers Comp - Net Periodic Costs (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Schedule of Net Periodic Benefit Costs and Assumptions for Defined Benefit Postretirement Plans [Line Items]
Amortization of actuarial gain	$ 11,198	$ 21,055	$ 32,705	$ 69,802
Net periodic (benefit) cost	(22,741)	19,139	14,390	83,665
Coal Workers Pneumoconiosis [Member]
Schedule of Net Periodic Benefit Costs and Assumptions for Defined Benefit Postretirement Plans [Line Items]
Service cost	1,419	2,135	4,255	6,405
Interest cost	1,384	1,808	4,153	5,424
Amortization of actuarial gain	(1,549)	(4,213)	(4,647)	(12,638)
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	(270)	3,761	(809)
Payments for Coal Workers Pnenumoconiosis			8,870
Workers Compensation [Member]
Schedule of Net Periodic Benefit Costs and Assumptions for Defined Benefit Postretirement Plans [Line Items]
Service cost	2,446	3,533	7,336	10,599
Interest cost	894	1,655	2,683	4,966
Amortization of actuarial gain	(96)	(699)	(287)	(2,098)
State administrative fees and insurance bond premiums	999	1,496	3,039	4,500
Legal and administrative costs	0	591	0	1,773
Net periodic (benefit) cost	4,243	6,576	12,771	19,740
Payments for workers compensation benefits, state administrative fees and surety bond premiums			11,327
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		(167)		(497)
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		$ 2,474		$ 7,327