Consolidated Balance Sheets (Parenthetical)	Dec. 31, 2012	Dec. 31, 2011
Partners' capital:
Class C convertible preferred unitholders issued (in units)	16,666,667	16,666,667
Class C convertible preferred unitholders outstanding (in units)	16,666,667	16,666,667
General partner, issued (in units)	51,036	35,729
General partner, outstanding (in units)	51,036	35,729
Limited Partners-Public Common [Member]
Partners' capital:
Limited partners unitholders, issued (in units)	51,299,278	17,292,279
Limited partners unitholders, outstanding (in units)	51,299,121	17,292,279
Limited Partners-Affiliated - Common [Member]
Partners' capital:
Limited partners unitholders, issued (in units)	7,145,866	11,297,737
Limited partners unitholders, outstanding (in units)	7,145,866	11,297,737
Limited Partners-Affiliated - Subordinated [Member]
Partners' capital:
Limited partners unitholders, issued (in units)	0	7,145,866
Limited partners unitholders, outstanding (in units)	0	7,145,866