Condensed Consolidated Statements of Changes in Partners' Capital (Deficit) (Unaudited) - USD ($) $ in Thousands	Total	Limited Partner [Member]	Preferred Partner [Member]	General Partner [Member]
Balance at Dec. 31, 2018	$ (6,896)	$ 370,972	$ 253,923	$ (631,791)
Net income (loss)	7,113	(5,557)	12,558	112
Equity-based incentive compensation	363	353		10
Distributions	(17,821)	(4,980)	(12,558)	(283)
Proceeds from sale of common units pursuant to the Employee Unit Purchase Plan	73	73
Balance at Jun. 30, 2019	(17,168)	360,861	253,923	(631,952)
Balance at Mar. 31, 2019	(12,739)	365,220	253,923	(631,882)
Net income (loss)	3,356	(2,976)	6,279	53
Equity-based incentive compensation	294	289		5
Distributions	(8,079)	(1,672)	(6,279)	(128)
Balance at Jun. 30, 2019	(17,168)	360,861	253,923	(631,952)
Balance at Dec. 31, 2019	(21,323)	356,777	253,923	(632,023)
Net income (loss)	1,351	(11,228)	12,558	21
Equity-based incentive compensation	427	420		7
Distributions	(16,188)	(3,373)	(12,558)	(257)
Proceeds from sale of common units pursuant to the Employee Unit Purchase Plan	55	55
Balance at Jun. 30, 2020	(35,678)	342,651	253,923	(632,252)
Balance at Mar. 31, 2020	(29,242)	348,983	253,923	(632,148)
Net income (loss)	1,351	(4,949)	6,279	21
Equity-based incentive compensation	319	315		4
Distributions	(8,106)	(1,698)	(6,279)	(129)
Balance at Jun. 30, 2020	$ (35,678)	$ 342,651	$ 253,923	$ (632,252)