Income Taxes Income Tax Reconciliation (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2012
Amount
Income Tax Reconciliation, Nondeductible Expense, Depletion		$ 111,104	$ 53,932
Percent
Statutory U.S. Federal Income Tax Rate		35.00%
Income Tax Expense / Effective Rate		809.90%	20.20%
Unusual or Infrequent, Tax Effect	$ 8,467	$ 4,701