Condensed Consolidating Financial Information (Condensed Consolidating Statements of Cash Flows) (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
Net cash provided by (used in) operating activities	$ 837,390	$ 856,930
Capital investments	(1,140,661)	(1,024,658)
Proceeds from sale of property and equipment	174,337	121,133
Transfers to restricted cash	(167,750)	(85,002)
Transfers From Restricted Cash	23,366
Other	8,895	3,879
Net cash used in investing activities	(1,101,813)	(984,648)
Payment on current portion of long-term debt	(600)	(600)
Payments on revolving long-term debt	(1,273,700)	(1,717,600)
Borrowings under revolving long-term debt	602,200	1,840,600
Proceeds from issuance of long-term debt	998,780
Other Items	(36,370)	2,415
Net cash provided by (used in) financing activities	290,310	124,815
Effect of exchange rate changes on cash	(15)	127
Increase (decrease) in cash and cash equivalents	25,872	(2,776)
Cash and cash equivalents at beginning of year	15,627	16,055
Cash and cash equivalents at end of period	41,499	13,279
Parent [Member]
Net cash provided by (used in) operating activities	(51,093)	(29,781)
Capital investments	(18,079)	(35,347)
Transfers to restricted cash	(167,750)	(85,002)
Transfers From Restricted Cash	23,366
Other	10,584	7,244
Net cash used in investing activities	(151,879)	(113,105)
Intercompany activities	(65,161)	22,870
Payment on current portion of long-term debt	(600)	(600)
Payments on revolving long-term debt	(1,273,700)	(1,717,600)
Borrowings under revolving long-term debt	602,200	1,840,600
Proceeds from issuance of long-term debt	998,780
Other Items	(36,370)	2,415
Net cash provided by (used in) financing activities	225,149	147,685
Increase (decrease) in cash and cash equivalents	22,177	4,799
Cash and cash equivalents at beginning of year	14,711	8,381
Cash and cash equivalents at end of period	36,888	13,180
Guarantors [Member]
Net cash provided by (used in) operating activities	624,945	763,933
Capital investments	(1,032,169)	(889,700)
Proceeds from sale of property and equipment	168,391	120,892
Other	(10,809)	(11,339)
Net cash used in investing activities	(874,587)	(780,147)
Intercompany activities	253,851	8,583
Net cash provided by (used in) financing activities	253,851	8,583
Increase (decrease) in cash and cash equivalents	4,209	(7,631)
Cash and cash equivalents at beginning of year		7,631
Cash and cash equivalents at end of period	4,209
Non-Guarantors [Member]
Net cash provided by (used in) operating activities	263,538	122,778
Capital investments	(90,413)	(99,611)
Proceeds from sale of property and equipment	5,946	241
Other	9,120	7,974
Net cash used in investing activities	(75,347)	(91,396)
Intercompany activities	(188,690)	(31,453)
Net cash provided by (used in) financing activities	(188,690)	(31,453)
Effect of exchange rate changes on cash	(15)	127
Increase (decrease) in cash and cash equivalents	(514)	56
Cash and cash equivalents at beginning of year	916	43
Cash and cash equivalents at end of period	$ 402	$ 99