Income Taxes Income Tax Components (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014 Rate	Dec. 31, 2013 Rate	Dec. 31, 2012 Rate
Income Tax Contingency [Line Items]
Valuation Allowance, Deferred Tax Asset, Change in Amount	$ 16	$ 4
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount	7,784
Unrecognized Tax Benefits	4,265	2,071
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	35.00%	35.00%	35.00%
Effective Income Tax Rate Reconciliation, Tax Settlement, State and Local, Amount	5,249	(2,399)	(8,737)
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Depletion, Amount	$ (43,140)	$ (51,104)	$ (49,572)