Consolidated Balance Sheets (Parenthetical) - shares
Dec. 31, 2015
Dec. 31, 2014
General partner units, authorized (in units) 461,136 427,083
General partner units, issued (in units) 461,136 427,083
Common units    
Limited partnership units, authorized (in units) 11,947,127 10,213,545
Limited partnership units, issued (in units) 11,947,127 10,213,545
Class A units    
Limited partnership units, authorized (in units) 250,000 250,000
Limited partnership units, issued (in units) 185,000 220,000
Subordinated units    
Limited partnership units, authorized (in units) 10,463,545 10,463,545
Limited partnership units, issued (in units) 10,463,545 10,463,545