CONSOLIDATED AND CONDENSED STATEMENTS OF CAPITAL (Unaudited) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended			6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012		Jun. 30, 2013	Jun. 30, 2012
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning Balance				$ 357,962	$ 337,187
Net income	9,078	10,028	[1]	25,715	22,495	[1]
Follow-on public offering					91,361
General partner contribution				37	1,951
Cash distributions				(42,052)	(38,888)
Unit-based compensation				479	118
Adjustment in fair value of derivatives					(563)
Purchase of treasury units				(250)	(221)
Ending Balance	341,891	413,440		341,891	413,440
Parent Net Investment [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning Balance					51,571	[1]
Net income					4,774	[1]
Ending Balance		56,345	[1]		56,345	[1]
Accumulated Other Comprehensive Income (Loss) [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning Balance					626
Adjustment in fair value of derivatives					(563)
Ending Balance		63			63
Limited Partner [Member] | Common Limited [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning Balance				349,490	279,562
Beginning Balance (in units)				26,566,776	20,471,776
Net income				25,201	14,566
Follow-on public offerings (in units)					2,645,000
Follow-on public offering					91,361
Issuance of restricted units				63,750
Forfeiture of restricted units (in units)				(250)
Cash distributions				(41,135)	(35,253)
Unit-based compensation				479	118
Purchase of treasury units (in units)				(6,000)
Purchase of treasury units				(250)	(221)
Ending Balance (in units)	26,624,276	23,116,776		26,624,276	23,116,776
Ending Balance	333,785	350,133		333,785	350,133
General Partner [Member]
Increase (Decrease) in Partners' Capital [Roll Forward]
Beginning Balance				8,472	5,428
Net income				514	3,155
General partner contribution				37	1,951
Cash distributions				(917)	(3,635)
Ending Balance	$ 8,106	$ 6,899		$ 8,106	$ 6,899

[1] Financial information for 2012 has been revised to include results attributable to the Redbird Class A interests and the Blending and Packaging Assets acquired from Cross prior to October 2, 2012. See Note 1 – General.