Debt and Other Long-Term Liabilities (Schedule Of Debt And Other Long-Term Liabilities) (Details) - USD ($) $ in Thousands		Jun. 30, 2016	Dec. 31, 2015
Debt
Principal		$ 758,587	$ 886,283
Unamortized discount and deferred financing fees	[1]	(8,348)	(10,413)
Total		750,239	875,870
Less: current portion		(15,000)	(13,125)
Total long-term portion		735,239	862,745
Other Liabilities
Capital Lease Obligations		5,531	5,889
Capital Lease Obligations, Current		(3,418)	(4,006)
Capital Lease Obligations, Noncurrent		2,113	1,883
Asset Retirement Obligations		9,438	9,412
Asset Retirement Obligation, Current		0	0
Asset Retirement Obligations, Noncurrent		9,438	9,412
Other Long-term Liabilities		19,780	19,477
Other Long-term Liabilities, Current		0	0
Other Long-term Liabilities, Noncurrent		19,780	19,477
Long-term debt and other long-term liabilities		784,988	910,648
Current portion of long-term debt and other long-term liabilities		(18,418)	(17,131)
Long-term debt and other long-term liabilities		766,570	893,517
Senior Notes | Senior Unsecured Notes due 2019
Debt
Principal		320,614	350,000
Unamortized discount and deferred financing fees	[1]	(2,922)	(3,770)
Total		317,692	346,230
Less: current portion		0	0
Total long-term portion		317,692	346,230
Senior Notes | Senior Unsecured Notes due 2021
Debt
Principal		228,598	258,908
Unamortized discount and deferred financing fees	[1]	(3,234)	(4,083)
Total		225,364	254,825
Less: current portion		0	0
Total long-term portion		225,364	254,825
Term Loans | Credit Facility
Debt
Principal		129,375	136,875
Unamortized discount and deferred financing fees	[1]	(224)	(260)
Total		129,151	136,615
Less: current portion		(15,000)	(13,125)
Total long-term portion		114,151	123,490
Revolving Line of Credit | Credit Facility
Debt
Principal		80,000	140,500
Unamortized discount and deferred financing fees	[1]	(1,968)	(2,300)
Total		78,032	138,200
Less: current portion		0	0
Total long-term portion		$ 78,032	$ 138,200

[1] As described in Note 1: Basis of Presentation and Principles of Consolidation, we adopted ASU 2015-03 and 2015-15 in the first quarter of 2016 and have applied the guidance to our Senior Notes and Credit Facility. Under this guidance, we are now presenting unamortized deferred financing fees as a direct deduction from the associated debt liability. Historically, unamortized deferred financing fees were included in other non-current assets. This adoption resulted in the reclassification of $3.8 million of unamortized deferred financing fees as of December 31, 2015, from other non-current assets to long-term debt in our Consolidated Balance Sheets. Deferred financing fees are amortized on a straight line basis over the life of the related loan.