v2.4.0.8
Income Taxes Income Tax Reconciliation (Details) (USD $)
In Thousands, unless otherwise specified
6 Months Ended
Jun. 30, 2013
Jun. 30, 2012
Amount    
Income Tax Reconciliation, Nondeductible Expense, Depletion $ 25,471 $ 39,275
Percent    
Statutory U.S. Federal Income Tax Rate 35.00% 35.00%
Income Tax Expense / Effective Rate 2969.40% 24.30%