Segment Information (Details Textuals) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Segment Reporting Information [Line Items]
Sales to external customers	$ 1,944,312	$ 1,791,288	$ 2,013,942
Purchased gas, NGLs and crude oil	(1,546,987)	(1,397,530)	(1,638,777)
Operating expenses	(150,858)	(130,882)	(111,778)
Loss on derivatives	2,304	1,006	7,776
Depreciation, amortization and impairments	(212,861)	(162,300)	(125,358)
Identifiable assets	2,848,827	2,426,475
LIG Operating Segments [Member]
Segment Reporting Information [Line Items]
Sales to external customers	491,217	561,389	811,216
RevenuesFromTransactionswithOtherSegmentsofSameEntity	89,081	225,542	128,130
Purchased gas, NGLs and crude oil	(495,807)	(678,188)	(809,471)
Operating expenses	(31,699)	(33,817)	(35,434)
Segment Profit Loss	52,792	74,926	94,441
Loss on derivatives	(92)	(3,440)	6,145
Depreciation, amortization and impairments	(12,706)	(13,936)	(13,676)
Property, Plant and Equipment, Additions	45,569	4,059	2,820
Identifiable assets	301,431	279,755	305,359
NTX Operating Segments [Member]
Segment Reporting Information [Line Items]
Sales to external customers	321,025	269,302	332,026
RevenuesFromTransactionswithOtherSegmentsofSameEntity	72,960	96,177	100,527
Purchased gas, NGLs and crude oil	(229,687)	(180,116)	(262,708)
Operating expenses	(53,772)	(55,582)	(48,807)
Segment Profit Loss	110,526	129,781	121,038
Loss on derivatives	1,768	4,405	1,896
Depreciation, amortization and impairments	(79,303)	(83,492)	(76,535)
Property, Plant and Equipment, Additions	23,175	45,235	73,069
Identifiable assets	991,332	1,057,504	1,113,431
PNGL Operating Segments [Member]
Segment Reporting Information [Line Items]
Sales to external customers	850,245	852,560	870,700
RevenuesFromTransactionswithOtherSegmentsofSameEntity	22,144	145,569	40,185
Purchased gas, NGLs and crude oil	(777,989)	(924,240)	(835,440)
Operating expenses	(30,735)	(29,601)	(27,537)
Segment Profit Loss	63,665	44,288	47,908
Loss on derivatives	289	41	(265)
Depreciation, amortization and impairments	(106,412)	(57,652)	(31,271)
Property, Plant and Equipment, Additions	394,514	182,782	25,618
Identifiable assets	1,003,596	632,962	460,865
ORV Operating Segments [Member]
Segment Reporting Information [Line Items]
Sales to external customers	281,825	108,037	0
RevenuesFromTransactionswithOtherSegmentsofSameEntity	0	0	0
Purchased gas, NGLs and crude oil	(227,689)	(82,274)	0
Operating expenses	(34,652)	(11,882)	0
Segment Profit Loss	19,484	13,881	0
Loss on derivatives	339	0	0
Depreciation, amortization and impairments	(11,591)	(4,861)	0
Property, Plant and Equipment, Additions	99,127	3,893	0
Identifiable assets	407,121	316,927	0
Corporate Elimination [Member]
Segment Reporting Information [Line Items]
Sales to external customers	0	0	0
RevenuesFromTransactionswithOtherSegmentsofSameEntity	(184,185)	(467,288)	(268,842)
Purchased gas, NGLs and crude oil	184,185	467,288	268,842
Operating expenses	0	0	0
Segment Profit Loss	0	0	0
Loss on derivatives	0	0	0
Depreciation, amortization and impairments	(2,849)	(2,359)	(3,876)
Property, Plant and Equipment, Additions	4,465	8,944	2,629
Identifiable assets	145,347	139,327	82,961
Total [Member]
Segment Reporting Information [Line Items]
Sales to external customers	1,944,312	1,791,288	2,013,942
RevenuesFromTransactionswithOtherSegmentsofSameEntity	0	0	0
Purchased gas, NGLs and crude oil	(1,546,987)	(1,397,530)	(1,638,777)
Operating expenses	(150,858)	(130,882)	(111,778)
Segment Profit Loss Total	246,467	262,876	263,387
Property, Plant and Equipment, Additions	566,850	244,913	104,136
Identifiable assets	$ 2,848,827	$ 2,426,475	$ 1,962,616