Condensed Consolidating Financial Information (Condensed Consolidating Statements of Cash Flows) (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Net cash provided by (used in) operating activities	$ 1,192,477	$ 1,300,211
Capital investments	(1,623,751)	(1,543,549)
Proceeds from sale of property and equipment	201,161	121,546
Transfers to restricted cash	(167,774)	(85,040)
Transfers from Restricted Cash	40,700	15,779
Other	5,239	4,940
Net cash used in investing activities	(1,544,425)	(1,486,324)
Payments on current portion of long-term debt	(600)	(600)
Payments on revolving long-term debt	(1,774,000)	(2,575,000)
Borrowings under revolving long-term debt	1,129,000	2,753,600
Proceeds from issuance of long-term debt	998,780
Other Items	1,711	5,254
Net cash provided by (used in) financing activities	354,891	183,254
Effect of exchange rate changes on cash	(10)	97
Increase (decrease) in cash and cash equivalents	2,933	(2,762)
Cash and cash equivalents at beginning of year	15,627	16,055
Cash and cash equivalents at end of period	18,560	13,293
Parent [Member]
Net cash provided by (used in) operating activities	(55,324)	(23,901)
Capital investments	(38,946)	(53,085)
Proceeds from sale of property and equipment	144
Transfers to restricted cash	(167,774)	(85,040)
Transfers from Restricted Cash	40,700	15,779
Other	16,575	11,046
Net cash used in investing activities	(149,301)	(111,300)
Intercompany activities	(148,027)	(44,592)
Payments on current portion of long-term debt	(600)	(600)
Payments on revolving long-term debt	(1,774,000)	(2,575,000)
Borrowings under revolving long-term debt	1,129,000	2,753,600
Proceeds from issuance of long-term debt	998,780
Other Items	1,722	5,254
Net cash provided by (used in) financing activities	206,875	138,662
Increase (decrease) in cash and cash equivalents	2,250	3,461
Cash and cash equivalents at beginning of year	14,711	8,381
Cash and cash equivalents at end of period	16,961	11,842
Guarantors [Member]
Net cash provided by (used in) operating activities	915,885	1,146,062
Capital investments	(1,452,061)	(1,333,977)
Proceeds from sale of property and equipment	169,149	121,281
Other	(24,340)	(31,564)
Net cash used in investing activities	(1,307,252)	(1,244,260)
Intercompany activities	392,732	92,018
Net cash provided by (used in) financing activities	392,732	92,018
Increase (decrease) in cash and cash equivalents	1,365	(6,180)
Cash and cash equivalents at beginning of year		7,631
Cash and cash equivalents at end of period	1,365	1,451
Non-Guarantors [Member]
Net cash provided by (used in) operating activities	331,916	178,050
Capital investments	(132,744)	(156,487)
Proceeds from sale of property and equipment	31,868	265
Other	13,004	25,458
Net cash used in investing activities	(87,872)	(130,764)
Intercompany activities	(244,705)	(47,426)
Other Items	(11)
Net cash provided by (used in) financing activities	(244,716)	(47,426)
Effect of exchange rate changes on cash	(10)	97
Increase (decrease) in cash and cash equivalents	(682)	(43)
Cash and cash equivalents at beginning of year	916	43
Cash and cash equivalents at end of period	$ 234