Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Segment information
Revenue	$ 395,421	$ 306,755	$ 768,879	$ 702,733
Purchased product costs	155,359	112,731	307,916	267,286
Facility expenses	62,797	48,230	122,307	96,555
Income from operations	140,022	257,741	203,685	308,233
Capital expenditures			1,435,084	580,980
Total reportable segments
Segment information
Revenue	396,858	308,079	771,680	705,950
Purchased product costs	155,359	112,731	307,916	267,286
Net operating margin	241,499	195,348	463,764	438,664
Facility expenses	65,117	50,735	126,929	101,298
Portion of operating income (loss) attributable to non-controlling interests	(1,090)	(85)	(2,365)	(82)
Income from operations	177,472	144,698	339,200	337,448
Capital expenditures			1,430,184	577,248
Liberty Segment
Segment information
Revenue	120,057	59,477	228,554	135,054
Purchased product costs	16,993	8,018	35,786	32,653
Net operating margin	103,064	51,459	192,768	102,401
Facility expenses	22,272	13,364	44,908	25,611
Income from operations	80,792	38,095	147,860	76,790
Capital expenditures			729,040	415,506
Utica Segment
Segment information
Revenue	3,594		4,217
Net operating margin	3,594		4,217
Facility expenses	6,412	283	10,374	283
Portion of operating income (loss) attributable to non-controlling interests	(1,143)	(113)	(2,482)	(113)
Income from operations	(1,675)	(170)	(3,675)	(170)
Capital expenditures			640,819	16,786
Northeast Segment
Segment information
Revenue	45,365	42,051	102,701	128,969
Purchased product costs	15,126	12,921	34,788	38,608
Net operating margin	30,239	29,130	67,913	90,361
Facility expenses	6,655	4,932	13,179	11,310
Income from operations	23,584	24,198	54,734	79,051
Capital expenditures			2,509	43,475
Southwest Segment
Segment information
Revenue	227,842	206,551	436,208	441,927
Purchased product costs	123,240	91,792	237,342	196,025
Net operating margin	104,602	114,759	198,866	245,902
Facility expenses	29,778	32,156	58,468	64,094
Portion of operating income (loss) attributable to non-controlling interests	53	28	117	31
Income from operations	74,771	82,575	140,281	181,777
Capital expenditures			57,816	101,481
Unallocated Segment
Segment information
Capital expenditures			$ 4,900	$ 3,732