Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012 item	Sep. 30, 2013	Sep. 30, 2012 item
Segment Information
Number of segments into which financial statements of Utica and Marcellus were combined due to the immateriality of Utica operations		1		1
Segment information
Revenue	$ 450,834	$ 316,976	$ 1,219,713	$ 1,019,709
Purchased product costs	191,672	119,369	499,588	386,655
Facility expenses	77,542	52,883	199,849	149,438
Income from operations	7,763	8,593	211,448	316,826
Capital expenditures			2,176,719	1,239,705
Total segments
Segment information
Revenue	452,377	318,233	1,224,057	1,024,183
Purchased product costs	191,672	119,369	499,588	386,655
Net operating margin	260,705	198,864	724,469	637,528
Facility expenses	79,397	55,378	206,326	156,676
Portion of operating loss attributable to non-controlling interests	(559)	(560)	(2,924)	(642)
Income from operations	181,867	144,046	521,067	481,494
Capital expenditures			2,170,836	1,234,793
Unallocated Segment
Segment information
Capital expenditures			5,883	4,912
Marcellus | Total segments
Segment information
Revenue	147,290	78,707	375,844	213,761
Purchased product costs	36,995	16,203	72,781	48,856
Net operating margin	110,295	62,504	303,063	164,905
Facility expenses	29,621	18,933	74,529	44,544
Income from operations	80,674	43,571	228,534	120,361
Capital expenditures			1,097,440	937,008
Utica Segment | Total segments
Segment information
Revenue	8,373	145	12,590	145
Net operating margin	8,373	145	12,590	145
Facility expenses	9,858	1,308	20,232	1,591
Portion of operating loss attributable to non-controlling interests	(599)	(627)	(3,081)	(740)
Income from operations	(886)	(536)	(4,561)	(706)
Capital expenditures			961,538	82,366
Northeast Segment | Total segments
Segment information
Revenue	48,829	39,987	151,530	168,956
Purchased product costs	15,330	11,054	50,118	49,662
Net operating margin	33,499	28,933	101,412	119,294
Facility expenses	7,359	6,267	20,538	17,577
Income from operations	26,140	22,666	80,874	101,717
Capital expenditures			3,418	70,206
Southwest Segment | Total segments
Segment information
Revenue	247,885	199,394	684,093	641,321
Purchased product costs	139,347	92,112	376,689	288,137
Net operating margin	108,538	107,282	307,404	353,184
Facility expenses	32,559	28,870	91,027	92,964
Portion of operating loss attributable to non-controlling interests	40	67	157	98
Income from operations	75,939	78,345	216,220	260,122
Capital expenditures			$ 108,440	$ 145,213