Consolidated Balance Sheets (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2012
Consolidated Balance Sheets
Class A limited partners, units par or assigned value (in dollars per unit)	$ 0	$ 0	$ 0
Class A limited partners, units authorized	7,500	7,500	7,500
Class A limited partners, units issued	7,500	7,500	7,500
Class A limited partners, units outstanding	7,500	7,500	7,500