Condensed Consolidating Financial Information (Condensed Consolidating Statements of Cash Flows) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Net cash provided by operating activities	$ 444,663	$ 396,479
Capital investments	(557,631)	(526,139)
Proceeds from sale of property and equipment	651	11,056
Other	1,770	(375)
Net cash used in investing activities	(555,210)	(515,458)
Intercompany activities	0	0
Payments on revolving long-term debt	(1,271,300)	(782,800)
Proceeds from issuance of long-term debt	998,780	0
Borrowings under revolving long-term debt	599,800	892,700
Other Items	(26,163)	10,389
Net cash provided by financing activities	301,117	120,289
Effect of exchange rate changes on cash	(30)	22
Increase (decrease) in cash and cash equivalents	190,540	1,332
Cash and cash equivalents at beginning of year	15,627	16,055
Cash and cash equivalents at end of period	206,167	17,387
Parent [Member]
Net cash provided by operating activities	(66,501)	(26,284)
Capital investments	(15,673)	(15,533)
Proceeds from sale of property and equipment	0	0
Other	4,085	3,574
Net cash used in investing activities	(11,588)	(11,959)
Intercompany activities	(32,324)	(75,684)
Payments on revolving long-term debt	(1,271,300)	(782,800)
Proceeds from issuance of long-term debt	998,780
Borrowings under revolving long-term debt	599,800	892,700
Other Items	(26,163)	10,389
Net cash provided by financing activities	268,793	44,605
Effect of exchange rate changes on cash	0	0
Increase (decrease) in cash and cash equivalents	190,704	6,362
Cash and cash equivalents at beginning of year	14,711	8,381
Cash and cash equivalents at end of period	205,415	14,743
Guarantors [Member]
Net cash provided by operating activities	428,743	359,234
Capital investments	(502,036)	(469,341)
Proceeds from sale of property and equipment	651	11,056
Other	(9,440)	(6,100)
Net cash used in investing activities	(510,825)	(464,385)
Intercompany activities	82,571	99,515
Payments on revolving long-term debt	0	0
Proceeds from issuance of long-term debt	0
Borrowings under revolving long-term debt	0	0
Other Items	0	0
Net cash provided by financing activities	82,571	99,515
Effect of exchange rate changes on cash	0	0
Increase (decrease) in cash and cash equivalents	489	(5,636)
Cash and cash equivalents at beginning of year	0	7,631
Cash and cash equivalents at end of period	489	1,995
Non-Guarantors [Member]
Net cash provided by operating activities	82,421	63,529
Capital investments	(39,922)	(41,265)
Proceeds from sale of property and equipment	0	0
Other	(7,125)	2,151
Net cash used in investing activities	(32,797)	(39,114)
Intercompany activities	(50,247)	(23,831)
Payments on revolving long-term debt	0	0
Proceeds from issuance of long-term debt	0
Borrowings under revolving long-term debt	0	0
Other Items	0	0
Net cash provided by financing activities	(50,247)	(23,831)
Effect of exchange rate changes on cash	(30)	22
Increase (decrease) in cash and cash equivalents	(653)	606
Cash and cash equivalents at beginning of year	916	43
Cash and cash equivalents at end of period	263	649
Eliminations [Member]
Net cash provided by operating activities	0	0
Capital investments	0	0
Proceeds from sale of property and equipment	0	0
Other	0	0
Net cash used in investing activities	0	0
Intercompany activities	0	0
Payments on revolving long-term debt	0	0
Proceeds from issuance of long-term debt	0
Borrowings under revolving long-term debt	0	0
Other Items	0	0
Net cash provided by financing activities	0	0
Effect of exchange rate changes on cash	0	0
Increase (decrease) in cash and cash equivalents	0	0
Cash and cash equivalents at beginning of year	0	0
Cash and cash equivalents at end of period	$ 0	$ 0