Partners Capital (Class B Preferred Units) (Details) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Mezzanine equity beginning balance	$ 342,991
Distributions	22,750	$ 24,918
Total mezzanine equity	343,416		$ 342,991
Class B Preferred
Mezzanine equity beginning balance	342,991	$ 172,111	172,111
Discount			(87)
Amortization of discount	1,300		23,477
Distributions	27,125		39,375
Distributions paid	(28,000)		(37,168)
Transfer embedded derivative to Class B			145,283
Total mezzanine equity	$ 343,416		$ 342,991