Condensed Consolidating Financial Information (Schedule Of Condensed Consolidating Balance Sheet) (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Condensed Balance Sheet Statements, Captions [Line Items]
Total current assets	$ 201,464	$ 278,621
Total property and equipment, net	2,824,445	2,629,253
Investment in subsidiaries	0	0
Other assets	51,841	73,602
Total Assets	3,077,750	2,981,476
Current liabilities	341,066	424,304
Long-term liabilities	1,456,671	1,453,731
Total shareholders’ equity	1,280,013	1,103,441
Total Liabilities and Shareholders’ Equity	3,077,750	2,981,476
Eliminations [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Total current assets	(2,281,833)	(2,346,986)
Total property and equipment, net	31,821	26,672
Investment in subsidiaries	(240,306)	(233,173)
Other assets	(90,521)	(67,172)
Total Assets	(2,580,839)	(2,620,659)
Current liabilities	(2,284,846)	(2,346,986)
Long-term liabilities	(69,492)	(50,415)
Total shareholders’ equity	(226,501)	(223,258)
Total Liabilities and Shareholders’ Equity	(2,580,839)	(2,620,659)
Parent Company [Member] | Reportable Legal Entities [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Total current assets	2,404,178	2,380,445
Total property and equipment, net	31,995	613
Investment in subsidiaries	240,306	233,173
Other assets	142,362	140,774
Total Assets	2,818,841	2,755,005
Current liabilities	173,022	296,686
Long-term liabilities	1,379,611	1,364,793
Total shareholders’ equity	1,266,208	1,093,526
Total Liabilities and Shareholders’ Equity	2,818,841	2,755,005
Combined Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Total current assets	79,119	245,051
Total property and equipment, net	2,757,601	2,562,029
Investment in subsidiaries	0	0
Other assets	0	0
Total Assets	2,836,720	2,807,080
Current liabilities	2,449,862	2,434,649
Long-term liabilities	146,552	139,353
Total shareholders’ equity	240,306	233,078
Total Liabilities and Shareholders’ Equity	2,836,720	2,807,080
Combined Non-Guarantor Subsidiaries [Member] | Reportable Legal Entities [Member]
Condensed Balance Sheet Statements, Captions [Line Items]
Total current assets	0	111
Total property and equipment, net	3,028	39,939
Investment in subsidiaries	0	0
Other assets	0	0
Total Assets	3,028	40,050
Current liabilities	3,028	39,955
Long-term liabilities	0	0
Total shareholders’ equity	0	95
Total Liabilities and Shareholders’ Equity	$ 3,028	$ 40,050