Partners' Capital (Cash Distributions) (Details) - USD ($) $ / shares in Units, $ in Thousands					3 Months Ended		9 Months Ended
	Nov. 15, 2016	Aug. 15, 2016	May 16, 2016	Feb. 16, 2016	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Distribution Made To Managing Member Or General Partner [Line Items]
Per Unit Distribution (in dollars per share)		$ 0.8255	$ 0.8173	$ 0.8013
Total Cash Distribution		$ 78,703	$ 77,921	$ 70,006			$ 285,895	$ 64,798
Distribution to IDR Holders		$ 20,348	$ 19,566	$ 16,532	$ 20,396	$ 8,441	$ 60,311	$ 13,252
Scenario, Forecast [Member]
Distribution Made To Managing Member Or General Partner [Line Items]
Per Unit Distribution (in dollars per share)	$ 0.8255
Total Cash Distribution	$ 78,889
Distribution to IDR Holders	$ 20,396