Condensed Consolidating Financial Information (Condensed Consolidating Statements of Cash Flows) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Net cash provided by (used in) operating activities	$ 1,908,528	$ 1,653,942	$ 1,739,817
Capital investments	(2,252,647)	(2,107,755)	(2,184,474)
Proceeds from sale of property and equipment		201,101	154,526
Transfers to restricted cash	8,542	(167,788)	(85,055)
Transfers from Restricted Cash		159,246	85,055
Other	10,166	8,519	5,158
Net cash used in investing activities	(2,215,776)	(1,906,677)	(2,024,790)
Payments on current portion of long-term debt	(1,200)	(1,200)	(1,200)
Payments on revolving long-term debt	(3,147,750)	(2,263,900)	(3,445,900)
Borrowings under revolving long-term debt	3,430,650	1,592,400	3,696,200
Proceeds from issuance of long-term debt		998,780
Other		(35,191)	35,203
Net cash provided by (used in) financing activities	277,199	290,889	284,303
Effect of exchange rate changes on cash	(596)	(198)	242
Increase (decrease) in cash and cash equivalents	(30,645)	37,956	(428)
Cash and cash equivalents at beginning of year	53,583	15,627	16,055
Cash and cash equivalents at end of year	22,938	53,583	15,627
Parent [Member]
Net cash provided by (used in) operating activities		(39,934)	14,688
Capital investments		(36,918)	(66,647)
Proceeds from sale of property and equipment		26,006
Transfers to restricted cash		(167,788)	(85,055)
Transfers from Restricted Cash		159,245	85,055
Other		(696)	16,263
Net cash used in investing activities		(20,151)	(50,384)
Intercompany activities		(198,023)	(242,277)
Payments on current portion of long-term debt		(1,200)	(1,200)
Payments on revolving long-term debt		(2,263,900)	(3,445,900)
Borrowings under revolving long-term debt		1,592,400	3,696,200
Other		(35,192)	35,203
Net cash provided by (used in) financing activities		92,865	42,026
Increase (decrease) in cash and cash equivalents		32,780	6,330
Cash and cash equivalents at beginning of year		14,711	8,381
Cash and cash equivalents at end of year		47,491	14,711
Guarantors [Member]
Net cash provided by (used in) operating activities		1,278,673	1,482,853
Capital investments		(1,868,487)	(1,916,246)
Proceeds from sale of property and equipment		169,149	154,261
Transfers from Restricted Cash		1
Other		(35,792)	(43,961)
Net cash used in investing activities		(1,735,129)	(1,805,946)
Intercompany activities		462,443	315,462
Other		1
Net cash provided by (used in) financing activities		462,444	315,462
Increase (decrease) in cash and cash equivalents		5,988	(7,631)
Cash and cash equivalents at beginning of year			7,631
Cash and cash equivalents at end of year		5,988
Non-Guarantors [Member]
Net cash provided by (used in) operating activities		415,203	242,276
Capital investments		(202,350)	(201,581)
Proceeds from sale of property and equipment		5,946	265
Other		45,007	32,856
Net cash used in investing activities		(151,397)	(168,460)
Intercompany activities		(264,420)	(73,185)
Net cash provided by (used in) financing activities		(264,420)	(73,185)
Effect of exchange rate changes on cash		(198)	242
Increase (decrease) in cash and cash equivalents		(812)	873
Cash and cash equivalents at beginning of year		916	43
Cash and cash equivalents at end of year		$ 104	$ 916