Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Buildings and equipment, accumulated depreciation	$ 8,366	$ 8,214
General partners’ capital, units issued (in units)	60,000	60,000
General partners’ capital, units outstanding (in units)	60,000	60,000
Limited partners’ capital, units issued (in units)	4,273,000	4,258,000
Limited partners’ capital, units outstanding (in units)	4,273,000	4,258,000