Debt and Other Long-Term Liabilities (Schedule Of Debt And Other Long-Term Liabilities) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Debt
Principal	$ 998,424	$ 745,523
Discount	(9,833)	(6,763)
Total	988,591	738,760
Less: current portion	(40,743)	(91,889)
Total long-term portion	947,848	646,871
Other Liabilities
Capital Lease Obligations	19,778	21,361
Capital Lease Obligations, Current	(12,265)	(11,997)
Capital Lease Obligations, Noncurrent	7,513	9,364
Asset retirement obligations	13,389	13,086
Asset Retirement Obligation, Current	0	0
Asset Retirement Obligations, Noncurrent	13,389	13,086
Other long-term liabilities	12,967	12,085
Other Long-term Liabilities, Current	0	(3)
Other Long-term Liabilities, Noncurrent	12,967	12,082
Current portion of long-term debt and other long-term liabilities	(53,008)	(103,889)
Long Term Debt And Other Long Term Liabilities	1,034,725	785,292
Long Term Debt And Other Liabilities Noncurrent	981,717	681,403
Unamortized deferred financing fees	5,577	5,026
Senior Notes | Senior Unsecured Notes due 2019
Debt
Principal	350,000	350,000
Discount	(4,806)	(5,317)
Total	345,194	344,683
Less: current portion	0	0
Total long-term portion	345,194	344,683
Other Liabilities
Unamortized deferred financing fees	773	832
Senior Notes | Senior Unsecured Notes due 2021
Debt
Principal	300,000	0
Discount	(4,473)	0
Total	295,527	0
Less: current portion	0	0
Total long-term portion	295,527	0
Other Liabilities
Unamortized deferred financing fees	1,478	0
Credit Facility
Other Liabilities
Unamortized deferred financing fees	82
Convertible Notes
Debt
Principal	33,424	51,148
Discount	(181)	(1,446)
Total	33,243	49,702
Less: current portion	(33,243)	(49,702)
Total long-term portion	0	0
Other Liabilities
Unamortized deferred financing fees	25	186
Term Loans | Credit Facility
Debt
Principal	150,000	344,375
Discount	(373)	0
Total	149,627	344,375
Less: current portion	(7,500)	(42,187)
Total long-term portion	142,127	302,188
Other Liabilities
Unamortized deferred financing fees	0	1,259
Revolving Line of Credit | Credit Facility
Debt
Principal	165,000	0
Discount	0	0
Total	165,000	0
Less: current portion	0	0
Total long-term portion	165,000	0
Other Liabilities
Unamortized deferred financing fees	$ 3,301	$ 2,749