Debt and Other Long-Term Liabilities (Schedule Of Debt And Other Long-Term Liabilities) (Details) - USD ($) $ in Thousands		Sep. 30, 2015	Dec. 31, 2014
Debt
Principal		$ 844,688	$ 956,250
Discount		(7,479)	(8,783)
Total		837,209	947,467
Less: current portion		(12,188)	(9,390)
Total long-term portion		825,021	938,077
Other Liabilities
Capital Lease Obligations		8,177	15,391
Capital Lease Obligations, Current		(5,680)	(11,026)
Capital Lease Obligations, Noncurrent		2,497	4,365
Asset retirement obligations		9,497	13,576
Asset Retirement Obligation, Current		0	0
Asset Retirement Obligations, Noncurrent		9,497	13,576
Other long-term liabilities		19,260	17,651
Other Long-term Liabilities, Current		0	0
Other Long-term Liabilities, Noncurrent		19,260	17,651
Long Term Debt And Other Long Term Liabilities		874,143	994,085
Current portion of long-term debt and other long-term liabilities		(17,868)	(20,416)
Long-term debt and other long-term liabilities		856,275	973,669
Unamortized deferred financing fees	[1]	4,214	4,986
Senior Notes | Senior Unsecured Notes due 2019
Debt
Principal		350,000	350,000
Discount		(3,530)	(4,296)
Total		346,470	345,704
Less: current portion		0	0
Total long-term portion		346,470	345,704
Other Liabilities
Unamortized deferred financing fees	[1]	534	649
Senior Notes | Senior Unsecured Notes due 2021
Debt
Principal		300,000	300,000
Discount		(3,670)	(4,152)
Total		296,330	295,848
Less: current portion		0	0
Total long-term portion		296,330	295,848
Other Liabilities
Unamortized deferred financing fees	[1]	1,213	1,372
Term Loans | Credit Facility
Debt
Principal		139,688	146,250
Discount		(279)	(335)
Total		139,409	145,915
Less: current portion		(12,188)	(9,390)
Total long-term portion		127,221	136,525
Other Liabilities
Unamortized deferred financing fees	[1]	0	0
Revolving Line of Credit | Credit Facility
Debt
Principal		55,000	160,000
Discount		0	0
Total		55,000	160,000
Less: current portion		0	0
Total long-term portion		55,000	160,000
Other Liabilities
Unamortized deferred financing fees	[1]	$ 2,467	$ 2,965

[1] Deferred financing fees are recorded in other long-term assets in our Consolidated Balance Sheets and are amortized on a straight line basis over the life of the related loan.