Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Segment information
Revenue									$ 1,395,231	$ 1,534,434	$ 1,241,563
Purchased product costs									530,328	682,370	578,627
Facility expenses									208,385	173,598	151,449
Income from operations	61,825	9,562	258,902	51,439	(7,557)	207,801	133,214	(15,294)	381,728	318,164	188,462
Capital expenditures									1,951,427	551,281	458,668
Total reportable segments
Segment information
Revenue									1,402,672	1,549,819	1,241,563
Purchased product costs									530,328	682,370	578,627
Net operating margin									872,344	867,449	662,936
Facility expenses									218,820	183,236	158,650
Portion of operating income (loss) attributable to non-controlling interests									4,431	69,162	32,566
Income from operations									649,093	615,051	471,720
Capital expenditures									1,946,426	546,191	453,028
Southwest Segment
Segment information
Revenue									856,416	1,031,986	750,928
Purchased product costs									387,902	506,911	308,960
Net operating margin									468,514	525,075	441,968
Facility expenses									124,921	121,197	115,109
Portion of operating income (loss) attributable to non-controlling interests									5,790	5,431	6,440
Income from operations									337,803	398,447	320,419
Capital expenditures									170,543	106,061	118,056
Northeast Segment
Segment information
Revenue									225,818	268,884	384,724
Purchased product costs									68,402	91,612	252,827
Net operating margin									157,416	177,272	131,897
Facility expenses									24,106	27,126	19,513
Income from operations									133,310	150,146	112,384
Capital expenditures									84,542	51,280	2,179
Liberty Segment
Segment information
Revenue									319,867	248,949	105,911
Purchased product costs									74,024	83,847	16,840
Net operating margin									245,843	165,102	89,071
Facility expenses									65,825	34,913	24,028
Portion of operating income (loss) attributable to non-controlling interests										63,731	26,126
Income from operations									180,018	66,458	38,917
Capital expenditures									1,458,323	388,850	332,793
Utica Segment
Segment information
Revenue									571
Net operating margin									571
Facility expenses									3,968
Portion of operating income (loss) attributable to non-controlling interests									(1,359)
Income from operations									(2,038)
Capital expenditures									233,018
Unallocated Segment
Segment information
Capital expenditures									$ 5,001	$ 5,090	$ 5,640