Annual report pursuant to Section 13 and 15(d)

Fair Value - Additional Information (Details)

v3.8.0.1
Fair Value - Additional Information (Details)
$ / shares in Units, Bcf / d in Billions
 12 Months Ended
Dec. 21, 2017
USD ($)
$ / shares
Dec. 31, 2017
USD ($)
Bcf / d
Dec. 31, 2016
USD ($)
Mar. 30, 2016
USD ($)
Instrument
Schedule of Equity Method Investments [Line Items]        
Proceeds from sale of interest $ 7,600,000      
Lightfoot Capital Partners LP [Member]        
Schedule of Equity Method Investments [Line Items]        
Equity interest percentage   6.60% 6.60%  
Lightfoot GP [Member]        
Schedule of Equity Method Investments [Line Items]        
Equity interest percentage   1.50% 1.50%  
Minimum [Member] | Lightfoot Capital Partners LP [Member]        
Schedule of Equity Method Investments [Line Items]        
Discount rate percentage     15.30%  
Maximum [Member] | Lightfoot Capital Partners LP [Member]        
Schedule of Equity Method Investments [Line Items]        
Discount rate percentage     17.30%  
Cash Flow Hedging [Member]        
Schedule of Equity Method Investments [Line Items]        
Number of instruments terminated | Instrument       1
Notional amount       $ 26,300,000
Lightfoot Capital Partners LP [Member] | Arc Logistics Partners LP [Member]        
Schedule of Equity Method Investments [Line Items]        
Receiving and regasification terminal, volume per day (bcf/d) | Bcf / d   1.5    
Limited partner interest   40.00%    
Equity issued (in dollars per unit) | $ / shares $ 14.50      
Fair Value, Measurements, Recurring [Member]        
Schedule of Equity Method Investments [Line Items]        
Other equity securities   $ 2,958,315 $ 9,287,209  
Level 3 [Member] | Fair Value, Measurements, Recurring [Member]        
Schedule of Equity Method Investments [Line Items]        
Other equity securities   $ 2,958,315 $ 9,287,209  
Arc Terminal Joliet Holdings [Member]        
Schedule of Equity Method Investments [Line Items]        
Equity interest percentage   0.60%    
Required reinvestment $ 1,200,000      
Lightfoot and Arc Terminal Joliet Holdings [Member]        
Schedule of Equity Method Investments [Line Items]        
Percent of total assets, less than   0.50%    
Gulf LNG [Member] | Zenith [Member]        
Schedule of Equity Method Investments [Line Items]        
Interest acquired 4.16%      
Payments to acquire $ 27,300,000      
Arc Terminal Joliet Holdings [Member] | Lightfoot LP and Lightfoot GP [Member]        
Schedule of Equity Method Investments [Line Items]        
Interest acquired 13.50%      
Gulf LNG [Member] | Lightfoot Capital Partners LP [Member]        
Schedule of Equity Method Investments [Line Items]        
Proceeds from sale of interest $ 36,200,000      
Percentage of interest sold 5.52%      
Arc Logistics GP [Member] | Lightfoot GP [Member]        
Schedule of Equity Method Investments [Line Items]        
Proceeds from sale of interest $ 94,500,000      
Percentage of interest sold 100.00%