Fair Value Disclosures Fair Value Disclosure (Narrative) (Details) (USD $)	3 Months Ended	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 Accounts Receivable Credit Concentration Risk	Dec. 31, 2012 Accounts Receivable Credit Concentration Risk	Dec. 31, 2013 KC	Dec. 31, 2012 KC	Dec. 31, 2013 KC Underperforming Stores	Dec. 31, 2013 KC LGC and KC Stores Scheduled to Close in 2014	Dec. 31, 2013 KC Test Concept Stores	Dec. 31, 2013 Reed Minerals	Dec. 31, 2012 Reed Minerals	Aug. 31, 2012 Reed Minerals T	Dec. 31, 2013 Reed Minerals Market Approach	Dec. 31, 2013 Reed Minerals Income Approach
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Purchase price														$ 70,900,000
Contingent consideration	1,581,000	1,581,000	4,000,000
Change in estimate		(2,426,000)
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 the twelve months ended December 31, 2013)												100,000	0
Valuation technique weighting															25.00%	75.00%
Goodwill impairment charge	3,973,000	3,973,000	0	0
Tangible asset impairment charges							1,100,000	700,000	500,000	400,000	200,000
Long-term debt fair value	170,700,000	170,700,000	166,800,000
Long-term Debt	$ 170,683,000	$ 170,683,000	$ 166,000,000
Revenue from major customer, percentage					53.50%	48.90%