CONSOLIDATED BALANCE SHEETS (Parenthetical) - shares	Dec. 31, 2016	Dec. 31, 2015
Common units, units authorized	22,119,170	22,119,170
Common units, units issued	18,532,419	18,465,320
Common units, units outstanding	18,532,419	18,465,320
Subordinated units, units authorized	18,197,249	18,197,249
Subordinated units, units issued	18,124,071	18,127,678
Subordinated units, units outstanding	18,124,071	18,127,678