Fair Value Disclosure (Narrative) (Details) (USD $)				3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013	Mar. 31, 2014 Reed Minerals	Mar. 31, 2013 Reed Minerals	Aug. 31, 2012 Reed Minerals T	Oct. 01, 2010 Bellaire Corporation
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of trust assets							$ 5,000,000
Tons of coal sold from reserves covered in earn-out period for earn-out calculation						15,000,000.0
Earn-out payments (less than $0.1 million for three months ended March 31, 2013)				0	100,000
Long-term debt excluding capital leases	210,600,000	170,700,000	162,800,000
Long-term Debt			$ 162,000,000