XML 87 R69.htm IDEA: XBRL DOCUMENT v3.20.4
Fair Value Measurements (Details Textual) - USD ($)
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Fair value of notes payable $ 1,030,000,000.00 $ 1,060,000,000.00
Pipe and other equipment    
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]    
Impairment charge for equipments held in inventory $ 0