v3.8.0.1
UNIT-BASED COMPENSATION Table 1 - LTIP Compensation Expense (Details) - USD ($)
$ in Thousands
12 Months Ended
Mar. 01, 2016
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Unit-based awards, outstanding (units)   902,911 793,097  
Unit-based awards transferred (units) 730,288      
Compensation expense   $ 8,727 $ 8,294  
Restricted units, domestic employees [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Unit-based awards, outstanding (units)   736,746 647,340 0
Unit-based awards transferred (units) 586,524      
Compensation expense   $ 7,881 $ 5,980  
Restricted units, non-employee directors [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Unit-based awards, outstanding (units)   27,097 18,134 0
Unit-based awards transferred (units) 17,629      
Compensation expense   $ 251 $ 388  
Restricted units, international employees [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Unit-based awards, outstanding (units)   58,107 50,609 0
Unit-based awards transferred (units) 49,121      
Compensation expense   $ 595 $ 715  
Performance Units [Member]        
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]        
Unit-based awards, outstanding (units)   38,865 35,373  
Unit-based awards transferred (units) 77,014      
Compensation expense   $ 0 $ 1,211  
Performance units awarded and outstanding   80,961 77,014