UNIT-BASED COMPENSATION (Narrative) (Details) (USD $)
12 Months Ended 12 Months Ended 12 Months Ended 7 Months Ended 12 Months Ended 7 Months Ended 12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2013
Common Units
Long-term Incentive Plan
Dec. 31, 2013
Phantom Units
Dec. 31, 2012
Phantom Units
Dec. 31, 2011
Phantom Units
Dec. 31, 2013
Phantom Units
Granted in March 2013
Dec. 31, 2013
Phantom Units
Granted in October 2012
Apr. 30, 2013
DFW Net Profits Interests
holder
Dec. 31, 2013
DFW Net Profits Interests
Dec. 31, 2012
DFW Net Profits Interests
May 01, 2013
DFW Net Profits Interests
Apr. 30, 2013
SMLP Restricted Units
Dec. 31, 2013
SMP Net Profits Interests
Dec. 31, 2012
SMP Net Profits Interests
Dec. 31, 2009
Maximum
DFW Net Profits Interests
Dec. 31, 2009
Maximum
SMP Net Profits Interests
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]                                    
Units reserved for issuance pursuant to LTIP       5,000,000.0                            
Units available for future issuance       4,700,000                            
Award vesting period         3 years                   5 years      
Unrecognized non-cash compensation expense               $ 3,600,000                    
Remaining expected weighted-average vesting period of recognition of incremental non-cash compensation expense               2 years 7 months 31 days                    
Units forfeited (in shares)         4,041       0                  
Other disclosures                                    
Portion of membership interests authorized for issuance, percent                                 5.00% 7.50%
Number of holders of net profit interest                   7                
Payment to acquire vested net profit interests 11,957,000 0 0             12,200,000                
Restricted units exchanged for unvested net profit interests                           7,393        
Nonvested phantom and restricted units (in shares)         283,682 131,558 0           0          
Period of recognition of compensation expense                     4 years              
Non-cash compensation expense - prior periods (in dollars)                       600,000       500,000    
Compensation expense due to modification                       $ 1,400,000            
Portion of membership interests issued, percent                             6.355%      
Portion of membership interests forfeited, percent                             0.00%