Summary of Significant Accounting Policies (Details 4) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Summary of Significant Accounting Policies
Undiscounted aggregated estimated claims to be paid	$ 47,043,000	$ 43,501,000
Workers' compensation liability recorded on a discounted basis	40,477,000	36,987,000
Weighted average discount rate used for discounting liability to present value (as a percent)	0.68%
Decrease in the discounted claims liability due to one-percentage-point increase in discount rate	200,000
Increase in the discounted claims liability due to one-percentage-point decrease in discount rate	100,000
Discount factor used to calculate present value of the obligation pertaining to medical and disability benefits for black lung disease (as a percent)	4.44%	5.14%
Present value of obligation pertaining to medical and disability benefits	17,900,000	12,000,000
Medical and disability benefits for black lung disease, decrease in the discounted claims liability due to one-percentage-point increase in discount rate	3,100,000
Medical and disability benefits for black lung disease, increase in the discounted claims liability due to one-percentage-point decrease in discount rate	4,100,000
Foreign Currency Translation
Foreign currency remeasurement gain (loss) recognized in miscellaneous income	3,100,000	3,800,000
Deferred Financing Costs
Unamortized deferred financing costs	70,000,000	65,200,000
Deferred financing costs, current	17,500,000	15,200,000
Other subsidiaries except Jim Walter Resources | U.S. | Minimum
Significant Accounting Policies
Amount of claims retained per accident	1,000,000
Other subsidiaries except Jim Walter Resources | U.S. | Maximum
Significant Accounting Policies
Amount of claims retained per accident	2,000,000
Jim Walter Resources | Minimum
Significant Accounting Policies
Amount of claims retained per accident	$ 10,000,000