Condensed Consolidating Financial Information (Condensed Consolidating Statements of Cash Flows) (Details) (USD $) In Thousands	9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010
Net cash provided by (used in) operating activities	$ 1,300,211	$ 1,215,062
Capital investments	(1,543,549)	(1,506,079)
Proceeds from sale of property and equipment	121,546	348,379
Transfers to restricted cash	(85,040)	(355,865)
Transfers from restricted cash	15,779	1,689
Other	4,940	(2,632)
Net cash used in investing activities	(1,486,324)	(1,514,508)
Payments on current portion of long-term debt	(600)	(600)
Payments on revolving long-term debt	(2,575,000)	(2,043,600)
Borrowings under revolving long-term debt	2,753,600	2,336,100
Other	5,254	8,559
Net cash provided by financing activities	183,254	300,459
Effect of exchange rate changes on cash	97	0
Increase (decrease) in cash and cash equivalents	(2,762)	1,013
Cash and cash equivalents at beginning of year	16,055	13,184
Cash and cash equivalents at end of period	13,293	14,197
Parent [Member]
Net cash provided by (used in) operating activities	(23,901)	(46,565)
Capital investments	(53,085)	(33,915)
Transfers to restricted cash	(85,040)	(355,865)
Transfers from restricted cash	15,779	1,689
Other	11,046	9,437
Net cash used in investing activities	(111,300)	(378,654)
Intercompany activities	(44,592)	130,114
Payments on current portion of long-term debt	(600)	(600)
Payments on revolving long-term debt	(2,575,000)	(2,043,600)
Borrowings under revolving long-term debt	2,753,600	2,336,100
Other	5,254	8,559
Net cash provided by financing activities	138,662	430,573
Increase (decrease) in cash and cash equivalents	3,461	5,354
Cash and cash equivalents at beginning of year	8,381	7,378
Cash and cash equivalents at end of period	11,842	12,732
Guarantors [Member]
Net cash provided by (used in) operating activities	1,146,062	1,082,585
Capital investments	(1,333,977)	(1,231,500)
Proceeds from sale of property and equipment	121,281	347,150
Other	(31,564)	(18,440)
Net cash used in investing activities	(1,244,260)	(902,790)
Intercompany activities	92,018	(184,121)
Net cash provided by financing activities	92,018	(184,121)
Increase (decrease) in cash and cash equivalents	(6,180)	(4,326)
Cash and cash equivalents at beginning of year	7,631	5,776
Cash and cash equivalents at end of period	1,451	1,450
Non-Guarantors [Member]
Net cash provided by (used in) operating activities	178,050	179,042
Capital investments	(156,487)	(240,664)
Proceeds from sale of property and equipment	265	1,229
Other	25,458	6,371
Net cash used in investing activities	(130,764)	(233,064)
Intercompany activities	(47,426)	54,007
Net cash provided by financing activities	(47,426)	54,007
Effect of exchange rate changes on cash	97
Increase (decrease) in cash and cash equivalents	(43)	(15)
Cash and cash equivalents at beginning of year	43	30
Cash and cash equivalents at end of period		$ 15