Debt and Other Long-Term Liabilities (Schedule Of Debt And Other Long-Term Liabilities) (Details) - USD ($) $ in Thousands		Dec. 31, 2015	Dec. 31, 2014
Debt
Principal		$ 886,283	$ 956,250
Discount		(6,564)	(8,783)
Total		879,719	947,467
Less: current portion		(13,125)	(9,390)
Total long-term portion		866,594	938,077
Other Liabilities
Capital Lease Obligations		5,889	15,391
Capital Lease Obligations, Current		(4,006)	(11,026)
Capital Lease Obligations, Noncurrent		1,883	4,365
Asset retirement obligations		9,412	13,576
Asset Retirement Obligation, Current		0	0
Asset Retirement Obligations, Noncurrent		9,412	13,576
Other long-term liabilities		19,477	17,651
Other Long-term Liabilities, Current		0	0
Other Long-term Liabilities, Noncurrent		19,477	17,651
Long Term Debt And Other Long Term Liabilities		914,497	994,085
Current portion of long-term debt and other long-term liabilities		(17,131)	(20,416)
Long-term debt and other long-term liabilities (Note 8)		897,366	973,669
Unamortized deferred financing fees	[1]	3,849	4,986
Senior Notes | Senior Unsecured Notes due 2019
Debt
Principal		350,000	350,000
Discount		(3,275)	(4,296)
Total		346,725	345,704
Less: current portion		0	0
Total long-term portion		346,725	345,704
Other Liabilities
Unamortized deferred financing fees	[1]	495	649
Senior Notes | 2021 Notes
Debt
Principal		258,908	300,000
Discount		(3,029)	(4,152)
Total		255,879	295,848
Less: current portion		0	0
Total long-term portion		255,879	295,848
Other Liabilities
Unamortized deferred financing fees	[1]	1,054	1,372
Credit Facility | Term Loans
Debt
Principal		136,875	146,250
Discount		(260)	(335)
Total		136,615	145,915
Less: current portion		(13,125)	(9,390)
Total long-term portion		123,490	136,525
Other Liabilities
Unamortized deferred financing fees	[1]	0	0
Credit Facility | Revolving Line of Credit
Debt
Principal		140,500	160,000
Discount		0	0
Total		140,500	160,000
Less: current portion		0	0
Total long-term portion		140,500	160,000
Other Liabilities
Unamortized deferred financing fees	[1]	$ 2,300	$ 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.