Condensed Consolidating Financial Information (Condensed Consolidating Statements of Cash Flows) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities	$ 608,866	$ 372,138
Capital investments	(533,787)	(483,634)
Proceeds from sale of property and equipment	16,794
Transfers from restricted cash		1,434
Other	1,309	1,038
Net cash used in investing activities	(515,684)	(481,162)
Payments on revolving long-term debt	(1,131,300)	(369,700)
Borrowings under revolving long-term debt	1,008,600	404,800
Other Items		37,845
Net cash provided by (used in) financing activities	(97,329)	72,945
Effect of exchange rate changes on cash	(72)	4
Increase (decrease) in cash and cash equivalents	(4,219)	(36,075)
Cash and cash equivalents at beginning of year	22,938	53,583
Cash and cash equivalents at end of period	18,719	17,508
Parent [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities		(55,189)
Capital investments		(17,873)
Transfers from restricted cash		1,434
Other		6,607
Net cash used in investing activities		(9,832)
Intercompany activities		(38,036)
Payments on revolving long-term debt		(369,700)
Borrowings under revolving long-term debt		404,800
Other Items		37,845
Net cash provided by (used in) financing activities		34,909
Increase (decrease) in cash and cash equivalents		(30,112)
Cash and cash equivalents at beginning of year		47,491
Cash and cash equivalents at end of period		17,379
Former Guarantors [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities		289,060
Capital investments		(453,651)
Other		(5,762)
Net cash used in investing activities		(459,413)
Intercompany activities		164,365
Net cash provided by (used in) financing activities		164,365
Increase (decrease) in cash and cash equivalents		(5,988)
Cash and cash equivalents at beginning of year		5,988
Other Subsidiaries [Member]
Condensed Cash Flow Statements, Captions [Line Items]
Net cash provided by (used in) operating activities		138,267
Capital investments		(12,110)
Other		193
Net cash used in investing activities		(11,917)
Intercompany activities		(126,329)
Net cash provided by (used in) financing activities		(126,329)
Effect of exchange rate changes on cash		4
Increase (decrease) in cash and cash equivalents		25
Cash and cash equivalents at beginning of year		104
Cash and cash equivalents at end of period		$ 129