Annual report pursuant to Section 13 and 15(d)

Introduction and Basis of Presentation - Narrative (Details)

v3.10.0.1
Introduction and Basis of Presentation - Narrative (Details)
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Pinedale LP      
Schedule of Equity Method Investments [Line Items]      
Equity interest percentage 100.00%    
Grand Isle Corridor LP      
Schedule of Equity Method Investments [Line Items]      
Equity interest percentage 100.00% 100.00% 100.00%