Consolidated Balance Sheets (Parenthetical) - shares	Jun. 30, 2015	Dec. 31, 2014
Common units [Member] | Westlake [Member]
Units issued	1,436,115	1,436,115
Units outstanding	1,436,115	1,436,115
Common units [Member] | Public [Member]
Units issued	12,937,500	12,937,500
Units outstanding	12,937,500	12,937,500
Subordinated units [Member] | Westlake [Member]
Units issued	12,686,115	12,686,115
Units outstanding	12,686,115	12,686,115