Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Consolidated Balance Sheets [Abstract]
Allowance for doubtful accounts receivable	$ 602	$ 1,407
General partner common units outstanding	89,638,312	89,583,950
Limited partners common units outstanding	10,499,844	10,516,844