Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Timber and roads, accumulated depletion	$ 123,239	$ 110,533
Buildings and equipment, accumulated depreciation	$ 8,038	$ 7,713
General partners’ capital, units issued	60,000	60,000
General partners’ capital, units outstanding	60,000	60,000
Limited partners’ capital, units issued	4,260,000	4,255,000
Limited partners’ capital, units outstanding	4,260,000	4,255,000