PARTNERS' CAPITAL AND MEMBERSHIP INTERESTS (Bison Acquisition) (Details) (USD $)
In Thousands, except Share data, unless otherwise specified
0 Months Ended 12 Months Ended 0 Months Ended 1 Months Ended 0 Months Ended 12 Months Ended 0 Months Ended 12 Months Ended 0 Months Ended 12 Months Ended 0 Months Ended 12 Months Ended 0 Months Ended 12 Months Ended
Jun. 04, 2013
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Jun. 04, 2013
General partner
Oct. 03, 2012
General partner
Mar. 31, 2013
General partner
Jun. 03, 2013
Bison Midstream
Jun. 04, 2013
Bison Midstream
Dec. 31, 2013
Bison Midstream
Jun. 04, 2013
Bison Midstream
General partner
Dec. 31, 2013
Bison Midstream
General partner
Jun. 04, 2013
Limited partners, Common
Bison Midstream
Dec. 31, 2013
Limited partners, Common
Bison Midstream
Jun. 04, 2013
General Partner Units
Bison Midstream
Dec. 31, 2013
General Partner Units
Bison Midstream
Jun. 04, 2013
Limited Partner Common and General Partner Units
Bison Midstream
Jun. 04, 2013
SMP Holdings' equity in Bison Midstream
Bison Midstream
Dec. 31, 2013
SMP Holdings' equity in Bison Midstream
Bison Midstream
Business Acquisition [Line Items]                                      
Cumulative percentage ownership after all transactions                 100.00%                    
Volume weighted average share price, term               5 days                      
Volume weighted average share price               $ 31.53                      
Cost of acquired entity, cash paid                 $ 200,000                 $ 200,000  
Units issued to acquire entity                   200,000   (978) (47,936)   (978)   (50,000) 248,914 248,914
Transaction costs   2,770 2,020 3,166                              
Units issued in connection with acquisition                   1,585,560     1,553,849 1,553,849 31,711 31,711      
Net assets in excess of consideration paid 56,535 56,535 0 0           0 1,131 1,131             (56,535)
Closing unit price                 $ 30.85                    
SMP Holdings' net investment in Bison Midstream                 $ 305,449                    
General partner interest (as a percent)         2.00% 2.00% 2.00%