Condensed Consolidating Financial Information (Condensed Consolidating Statements of Cash Flows) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Net cash provided by operating activities	$ 1,739,817	$ 1,642,585	$ 1,359,376
Capital investments	(2,184,474)	(2,073,174)	(1,780,165)
Proceeds from sale of property and equipment	154,526	350,227	818
Transfers to restricted cash	(85,055)	(356,035)	0
Transfers from restricted cash	85,055	356,035	0
Other	5,158	(2,684)	(1,257)
Net cash used in investing activities	(2,024,790)	(1,725,631)	(1,780,604)
Intercompany activities	0	0	0
Payments on current portion of long-term debt	(1,200)	(1,200)	(61,200)
Payments on revolving long-term debt	(3,445,900)	(2,958,100)	(1,371,700)
Borrowings under revolving long-term debt	3,696,200	3,054,800	1,696,200
Other	35,203	(9,260)	(25,165)
Net cash provided by financing activities	284,303	86,240	238,135
Effect of exchange rate changes on cash	242	(323)	0
Increase (decrease) in cash and cash equivalents	(428)	2,871	(183,093)
Cash and cash equivalents at beginning of year	16,055	13,184	196,277
Cash and cash equivalents at end of year	15,627	16,055	13,184
Parent [Member]
Net cash provided by operating activities	14,688	25,865	58,212
Capital investments	(66,647)	(46,062)	(17,075)
Proceeds from sale of property and equipment	0	0	0
Transfers to restricted cash	(85,055)	(356,035)
Transfers from restricted cash	85,055	356,035
Other	16,263	11,864	10,980
Net cash used in investing activities	(50,384)	(34,198)	(6,095)
Intercompany activities	(242,277)	(76,904)	(478,843)
Payments on current portion of long-term debt	(1,200)	(1,200)	(61,200)
Payments on revolving long-term debt	(3,445,900)	(2,958,100)	(1,371,700)
Borrowings under revolving long-term debt	3,696,200	3,054,800	1,696,200
Other	35,203	(9,260)	(25,165)
Net cash provided by financing activities	42,026	9,336	(240,708)
Effect of exchange rate changes on cash	0	0
Increase (decrease) in cash and cash equivalents	6,330	1,003	(188,591)
Cash and cash equivalents at beginning of year	8,381	7,378	195,969
Cash and cash equivalents at end of year	14,711	8,381	7,378
Guarantors [Member]
Net cash provided by operating activities	1,482,853	1,368,248	1,198,995
Capital investments	(1,916,246)	(1,718,847)	(1,517,990)
Proceeds from sale of property and equipment	154,261	348,274	763
Transfers to restricted cash	0	0
Transfers from restricted cash	0	0
Other	(43,961)	(22,719)	(29,238)
Net cash used in investing activities	(1,805,946)	(1,393,292)	(1,546,465)
Intercompany activities	315,462	26,899	353,246
Payments on current portion of long-term debt	0	0	0
Payments on revolving long-term debt	0	0	0
Borrowings under revolving long-term debt	0	0	0
Other	0	0	0
Net cash provided by financing activities	315,462	26,899	353,246
Effect of exchange rate changes on cash	0	0
Increase (decrease) in cash and cash equivalents	(7,631)	1,855	5,776
Cash and cash equivalents at beginning of year	7,631	5,776	0
Cash and cash equivalents at end of year	0	7,631	5,776
Non-Guarantors [Member]
Net cash provided by operating activities	242,276	248,472	102,169
Capital investments	(201,581)	(308,265)	(245,100)
Proceeds from sale of property and equipment	265	1,953	55
Transfers to restricted cash	0	0
Transfers from restricted cash	0	0
Other	32,856	8,171	17,001
Net cash used in investing activities	(168,460)	(298,141)	(228,044)
Intercompany activities	(73,185)	50,005	125,597
Payments on current portion of long-term debt	0	0	0
Payments on revolving long-term debt	0	0	0
Borrowings under revolving long-term debt	0	0	0
Other	0	0	0
Net cash provided by financing activities	(73,185)	50,005	125,597
Effect of exchange rate changes on cash	242	(323)
Increase (decrease) in cash and cash equivalents	873	13	(278)
Cash and cash equivalents at beginning of year	43	30	308
Cash and cash equivalents at end of year	916	43	30
Eliminations [Member]
Net cash provided by operating activities	0	0	0
Capital investments	0	0	0
Proceeds from sale of property and equipment	0	0	0
Transfers to restricted cash	0	0
Transfers from restricted cash	0	0
Other	0	0	0
Net cash used in investing activities	0	0	0
Intercompany activities	0	0	0
Payments on current portion of long-term debt	0	0	0
Payments on revolving long-term debt	0	0	0
Borrowings under revolving long-term debt	0	0	0
Other	0	0	0
Net cash provided by financing activities	0	0	0
Effect of exchange rate changes on cash	0	0
Increase (decrease) in cash and cash equivalents	0	0	0
Cash and cash equivalents at beginning of year	0	0	0
Cash and cash equivalents at end of year	$ 0	$ 0	$ 0