Condensed Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015		Jun. 30, 2016	Jun. 30, 2015
Revenues:
Total revenues	$ 578,602	$ 735,904		$ 1,046,641	$ 1,343,300
Cost of products sold:
Affiliate	123,870	162,191		219,019	292,699
Third-party	380,386	501,835		680,827	913,028
Operating and maintenance expenses	37,574	38,058		76,475	74,429
Selling, general and administrative expenses	5,758	6,279		10,823	12,234
Gain on disposal of assets, net	(802)	(160)		(901)	(244)
Depreciation and amortization	7,325	6,670		14,469	12,562
Total operating costs and expenses	554,111	714,873		1,000,712	1,304,708
Operating income	24,491	21,031		45,929	38,592
Other income (expense):
Interest and debt expense	6,414	6,248		13,466	10,212
Other income (expense), net	14	18		(104)	35
Net income before income taxes	18,091	14,801		32,359	28,415
Provision for income taxes	(217)	(148)		(478)	(351)
Net income	17,874	14,653		31,881	28,064
Less net loss attributable to General Partner	0	(1,262)	[1]	0	(3,174)	[1]
Net income attributable to limited partners	$ 17,874	$ 15,915		$ 31,881	$ 31,238
Earnings Per Share [Abstract]
Distribution Made to Limited Partner, Distributions Declared, Per Unit	$ 0.4025	$ 0.3475		$ 0.7950	$ 0.6800
Common Units [Member]
Earnings Per Share [Abstract]
Earnings Per Share, Basic	0.33	0.34		0.61	0.66
Earnings Per Share, Diluted	$ 0.33	$ 0.34		$ 0.61	$ 0.66
Weighted Average Number of Shares Outstanding, Basic	26,409	24,017		25,429	24,001
Weighted Average Number of Shares Outstanding, Diluted	26,427	24,051		25,441	24,023
Subordinated Units [Member]
Earnings Per Share [Abstract]
Earnings Per Share, Basic and Diluted	$ 0.36	$ 0.34		$ 0.64	$ 0.66
Weighted Average Number of Shares Outstanding, Basic and Diluted	22,811	22,811		22,811	22,811
Fee Based Revenues [Member]
Revenues:
Revenues: Affiliate	$ 53,965	$ 47,465		$ 105,893	$ 92,943
Revenues: Third-party	677	679		1,367	1,302
Sales Based Revenues [Member]
Revenues:
Revenues: Affiliate	126,525	164,576		224,054	297,347
Revenues: Third-party	$ 397,435	$ 523,184		$ 715,327	$ 951,708

[1] We apply the two-class method to calculate earnings per unit and allocate the results of operations of the TexNew Mex Pipeline System prior to the TexNew Mex Pipeline Acquisition entirely to our general partner. The limited partners had no rights to the results of operations before this acquisition.