CONSOLIDATED STATEMENTS OF PARTNERS' CAPITAL - USD ($) shares in Thousands, $ in Thousands	Total	Noncontrolling Interests	General Partners	Limited Partners
Beginning Balance (in units) at Dec. 31, 2016	4,315
Beginning balance at Dec. 31, 2016	$ 248,464	$ 189,331	$ 934	$ 58,199
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income (loss)	24,405	6,514	250	17,641
Cash distributions	(43,118)	(30,903)	(171)	(12,044)
Capital calls	$ 11,137	11,137
Equity-based compensation (in units)	15
Equity-based compensation	$ 1,128		16	1,112
Unit issuances - distribution reinvestment plan	$ 9			9
Unit repurchases (in units)	(18)
Unit repurchases	$ (1,305)			(1,305)
Indirect repurchase of units for minimum tax withholding (in units)	(1)
Indirect repurchase of units for minimum tax withholding	$ (94)		(1)	(93)
Beginning Balance (in units) at Dec. 31, 2017	4,311
Ending balance at Dec. 31, 2017	$ 240,626	176,079	1,028	63,519
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income (loss)	7,637	816	95	6,726
Cash distributions	(29,450)	(15,507)	(194)	(13,749)
Capital calls	$ 119,735	119,735
Equity-based compensation (in units)	17
Equity-based compensation	$ 1,127		16	1,111
Unit issuances - distribution reinvestment plan (in units)	3
Unit issuances - distribution reinvestment plan	$ 215			215
Unit repurchases (in units)	(17)
Unit repurchases	$ (1,189)			(1,189)
Indirect repurchase of units for minimum tax withholding (in units)	(1)
Indirect repurchase of units for minimum tax withholding	$ (101)		(1)	(100)
Beginning Balance (in units) at Dec. 31, 2018	4,313
Ending balance at Dec. 31, 2018	$ 338,600	281,123	944	56,533
Increase (Decrease) in Partners' Capital [Roll Forward]
Net income (loss)	(9,954)	(12,389)	34	2,401
Cash distributions	(27,321)	(9,886)	(242)	(17,193)
Capital calls	17,259	17,259
Preferred stock issuance	$ 125	125
Equity-based compensation (in units)	18
Equity-based compensation	$ 1,185		16	1,169
Unit issuances - distribution reinvestment plan (in units)	1
Unit issuances - distribution reinvestment plan	$ 42			42
Unit repurchases (in units)	(13)
Unit repurchases	$ (863)			(863)
Indirect repurchase of units for minimum tax withholding (in units)	(1)
Indirect repurchase of units for minimum tax withholding	$ (80)		(1)	(79)
Beginning Balance (in units) at Dec. 31, 2019	4,318
Ending balance at Dec. 31, 2019	$ 318,993	$ 276,232	$ 751	$ 42,010