v3.8.0.1
ACQUISITIONS Narrative 2 (Details) - USD ($)
$ in Thousands
12 Months Ended
Apr. 28, 2017
Apr. 18, 2017
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Business Acquisition [Line Items]          
General partner ownership interest     2.00% 2.00% 2.00%
Common Limited Partner [Member]          
Business Acquisition [Line Items]          
Issuance of units (units)   14,375,000 14,375,000 595,050  
Net proceeds from issuance of units     $ 643,878 $ 27,710  
General Partner [Member]          
Business Acquisition [Line Items]          
Net proceeds from issuance of units   $ 13,600 $ 13,597 $ 575  
General partner ownership interest     2.00%    
Series B Preferred Limited Partner [Member]          
Business Acquisition [Line Items]          
Issuance of units (units) 15,400,000        
Net proceeds from issuance of units $ 371,800        
5.625% senior notes          
Business Acquisition [Line Items]          
Senior notes issued $ 550,000        
Stated interest rate 5.625%   5.625%