Net Income (Loss) Per Limited Partner Unit - Undistributed Net Loss Attributable to Common and Subordinated Unitholders (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Net income (loss) attributable to partners:
Net income attributable to limited partners	$ 7,202	$ 6,737
Less: Distributions declared	(2,894)	(1,944)
Incentive distribution rights	(197)	(195)
Net income attributable to common and subordinated unitholders	3,755	4,598
General Partner
Net income (loss) attributable to partners:
Incentive distribution rights	(197)	(195)
Preferred Units
Net income (loss) attributable to partners:
Less: Distributions declared	(2,894)	(1,944)
Preferred Units Series C
Net income (loss) attributable to partners:
Accretion of Series C preferred units	(356)
Common Units
Net income (loss) attributable to partners:
Less: Distributions declared	(9,312)	(9,190)
Net income attributable to common and subordinated unitholders	3,755	4,901
Undistributed net loss	(5,557)	(4,289)
Common and Subordinated Units
Net income (loss) attributable to partners:
Undistributed net loss	$ (5,557)	$ (4,592)