Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Segment Reporting Information [Line Items]
Revenues	$ 468,643	$ 444,947	$ 1,369,069	$ 1,265,308
Sales to affiliates	0	0	0	0
Purchased gas, NGLs and crude oil	(368,349)	(345,202)	(1,068,465)	(975,507)
Operating expenses	(39,412)	(35,551)	(113,608)	(93,928)
Segment profits	60,882	64,194	186,996	195,873
Gain (loss) on derivatives	(1,634)	(759)	(1,662)	1,977
Depreciation, Amortization and Impairment, Total	(105,987)	(45,078)	(174,404)	(110,163)
Capital expenditures	157,618	49,385	447,331	132,180
Identifiable assets	2,692,565	2,353,874	2,692,565	2,353,874	2,426,475
LIG Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues	119,716	141,977	372,499	410,154
Sales to affiliates	22,949	50,304	68,854	183,529
Purchased gas, NGLs and crude oil	(121,910)	(166,374)	(377,937)	(509,196)
Operating expenses	(8,487)	(8,468)	(23,960)	(25,164)
Segment profits	12,268	17,439	39,456	59,323
Gain (loss) on derivatives	(584)	(498)	370	4,145
Depreciation, Amortization and Impairment, Total	(3,168)	(4,379)	(9,477)	(10,747)
Capital expenditures	10,842	1,596	27,010	3,484
Identifiable assets	282,945	281,891	282,945	281,891
NTX Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues	72,129	65,606	230,939	191,523
Sales to affiliates	21,839	22,278	55,309	70,988
Purchased gas, NGLs and crude oil	(54,460)	(41,807)	(160,255)	(123,284)
Operating expenses	(13,853)	(14,255)	(40,499)	(41,549)
Segment profits	25,655	31,822	85,494	97,678
Gain (loss) on derivatives	(510)	(293)	(1,557)	(2,709)
Depreciation, Amortization and Impairment, Total	(19,887)	(21,508)	(59,528)	(62,950)
Capital expenditures	4,821	7,596	12,073	41,050
Identifiable assets	989,583	1,067,591	989,583	1,067,591
PNGL Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues	181,327	184,427	550,811	610,694
Sales to affiliates	3,140	35,209	19,659	120,997
Purchased gas, NGLs and crude oil	(159,991)	(204,267)	(502,680)	(677,996)
Operating expenses	(6,847)	(7,306)	(22,067)	(21,693)
Segment profits	17,629	8,063	45,723	32,002
Gain (loss) on derivatives	(271)	32	(26)	541
Depreciation, Amortization and Impairment, Total	(78,652)	(16,503)	(94,842)	(32,531)
Capital expenditures	101,406	34,064	329,071	79,981
Identifiable assets	869,156	538,427	869,156	538,427
ORV Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues	95,471	52,937	214,820	52,937
Sales to affiliates	0	0	0	0
Purchased gas, NGLs and crude oil	(79,916)	(40,545)	(171,415)	(40,545)
Operating expenses	(10,225)	(5,522)	(27,082)	(5,522)
Segment profits	5,330	6,870	16,323	6,870
Gain (loss) on derivatives	(269)	0	(449)	0
Depreciation, Amortization and Impairment, Total	(3,451)	(2,164)	(8,561)	(2,164)
Capital expenditures	39,085	556	71,771	556
Identifiable assets	402,510	318,258	402,510	318,258
Corporate Elimination [Member]
Segment Reporting Information [Line Items]
Revenues	0	0	0	0
Sales to affiliates	(47,928)	(107,791)	(143,822)	(375,514)
Purchased gas, NGLs and crude oil	47,928	107,791	143,822	375,514
Operating expenses	0	0	0	0
Segment profits	0	0	0	0
Gain (loss) on derivatives	0	0	0	0
Depreciation, Amortization and Impairment, Total	(829)	(524)	(1,996)	(1,771)
Capital expenditures	1,464	5,573	7,406	7,109
Identifiable assets	$ 148,371	$ 147,707	$ 148,371	$ 147,707