Consolidated balance sheets (Parenthetical) - shares	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Consolidated balance sheets
Common unitholders, units issued	16,133,941	16,124,566
Common unitholders, units outstanding	16,133,941	16,124,566
General partner interest (as a percent)	2.00%	2.00%
General partner interest, equivalent units outstanding	329,264	329,073