Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Buildings and equipment, accumulated depreciation	$ 8,085	$ 7,833
General partners’ capital, units issued	60,000	60,000
General partners’ capital, units outstanding	60,000	60,000
Limited partners’ capital, units issued	4,254,000	4,251,000
Limited partners’ capital, units outstanding	4,254,000	4,251,000