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Segment Reporting - Additional Information (Details)
9 Months Ended
Sep. 30, 2021
Station
Segment
Sep. 30, 2020
Segment Reporting Information [Line Items]    
Number of reportable segments | Segment 2  
Number of operating segments | Segment 2  
Customer Concentration Risk [Member] | Revenues [Member] | One customer [Member]    
Segment Reporting Information [Line Items]    
Concentration risk, percentage 89.00% 87.00%
Concentration risk, additional characteristic one customer  
CNG Fueling Stations [Member]    
Segment Reporting Information [Line Items]    
Number of stations located | Station 3  
Additional number of stations located | Station 2