Equity, Cash Distributions (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended				6 Months Ended		0 Months Ended		3 Months Ended		6 Months Ended
	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Jul. 18, 2013 Cash distribution		Jun. 30, 2013 Cash distribution		Jun. 30, 2013 Cash distribution
Distribution Made to Member or Limited Partner
Total Quarterly Distribution Per Unit paid (dollars per unit)		$ 0.4900	$ 0.4725
Total Quarterly Distribution Per Unit declared (dollars per unit)	$ 0.51			$ 0.4100	$ 1.00	$ 0.7875	$ 0.51	[1]	$ 0.51	[1]
Total Cash Distribution including general partner IDRs paid		$ 23,976	$ 22,911
Total Cash Distribution including general partner IDRs declared	$ 26,108			$ 12,960	$ 50,084	$ 24,790			$ 26,108	[1]
Date of Distribution		May 14, 2013	Feb. 14, 2013								Aug. 14, 2013	[1]
Unitholders Record Date		May 03, 2013	Feb. 04, 2013								Aug. 02, 2013	[1]
Declaration date											Jul. 18, 2013

[1] This distribution was declared on July 18, 2013 and will be paid on the date of distribution.