Condensed Consolidating Financial Information (Schedule Of Condensed Consolidating Balance Sheet) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Current assets	$ 279,761	$ 206,823
Current assets held for sale	0	1,882
Assets of discontinued operations	0
Property and equipment, net	1,794,215	1,487,674
Investment in subsidiaries	0	0
Long-term assets held for sale	0	132,626
Other assets	36,784	54,991
TOTAL ASSETS	2,110,760	1,883,996
Current liabilities	311,899	250,255
Current liabilities associated with assets held for sale	0	48,663
Current liabilities of discontinued operations	10,936	0
Long-term liabilities	928,985	976,515
Long-term liabilities associated with assets held for sale	0	23,547
Long-term liabilities of discontinued operations	17,336	0
Shareholders’ equity	841,604	585,016	509,855	456,636
TOTAL LIABILITIES AND SHAREHOLDERS’ EQUITY	2,110,760	1,883,996
Parent Company [Member]
Current assets	1,820,069	1,689,430
Current assets held for sale	0	0
Assets of discontinued operations	0
Property and equipment, net	2,797	23,041
Investment in subsidiaries	61,619	14,588
Long-term assets held for sale	0	12,670
Other assets	69,686	46,913
TOTAL ASSETS	1,954,171	1,786,642
Current liabilities	190,550	179,221
Current liabilities associated with assets held for sale	0	9,880
Current liabilities of discontinued operations	10,936
Long-term liabilities	905,235	973,003
Long-term liabilities associated with assets held for sale	0	0
Long-term liabilities of discontinued operations	17,336
Shareholders’ equity	830,114	624,538
TOTAL LIABILITIES AND SHAREHOLDERS’ EQUITY	1,954,171	1,786,642
Combined Guarantor Subsidiaries [Member]
Current assets	168,718	130,487
Current assets held for sale	0	0
Assets of discontinued operations	0
Property and equipment, net	1,768,553	1,443,064
Investment in subsidiaries	0	0
Long-term assets held for sale	0	0
Other assets	0	16,928
TOTAL ASSETS	1,937,271	1,590,479
Current liabilities	1,828,314	1,631,887
Current liabilities associated with assets held for sale	0	0
Current liabilities of discontinued operations	0
Long-term liabilities	47,335	3,512
Long-term liabilities associated with assets held for sale	0	0
Long-term liabilities of discontinued operations	0
Shareholders’ equity	61,622	(44,920)
TOTAL LIABILITIES AND SHAREHOLDERS’ EQUITY	1,937,271	1,590,479
Combined Non-Guarantor Subsidiaries [Member]
Current assets	0	0
Current assets held for sale	0	1,882
Assets of discontinued operations	0
Property and equipment, net	2,058	0
Investment in subsidiaries	0	0
Long-term assets held for sale	0	119,956
Other assets	0	0
TOTAL ASSETS	2,058	121,838
Current liabilities	2,061	0
Current liabilities associated with assets held for sale	0	38,783
Current liabilities of discontinued operations	0
Long-term liabilities	0	0
Long-term liabilities associated with assets held for sale	0	23,547
Long-term liabilities of discontinued operations	0
Shareholders’ equity	(3)	59,508
TOTAL LIABILITIES AND SHAREHOLDERS’ EQUITY	2,058	121,838
Eliminations [Member]
Current assets	(1,709,026)	(1,613,094)
Current assets held for sale	0	0
Assets of discontinued operations	0
Property and equipment, net	20,807	21,569
Investment in subsidiaries	(61,619)	(14,588)
Long-term assets held for sale	0	0
Other assets	(32,902)	(8,850)
TOTAL ASSETS	(1,782,740)	(1,614,963)
Current liabilities	(1,709,026)	(1,560,853)
Current liabilities associated with assets held for sale	0	0
Current liabilities of discontinued operations	0
Long-term liabilities	(23,585)	0
Long-term liabilities associated with assets held for sale	0	0
Long-term liabilities of discontinued operations	0
Shareholders’ equity	(50,129)	(54,110)
TOTAL LIABILITIES AND SHAREHOLDERS’ EQUITY	$ (1,782,740)	$ (1,614,963)