Quarterly report pursuant to Section 13 or 15(d)

Fair Value - Additional Information (Details)

v3.7.0.1
Fair Value - Additional Information (Details)
$ in Millions
6 Months Ended 12 Months Ended
Jun. 30, 2017
Bcf / d
Dec. 31, 2016
Mar. 30, 2016
USD ($)
Instrument
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 15.70% 15.30%  
Maximum [Member] | Lightfoot Capital Partners LP [Member]      
Schedule of Equity Method Investments [Line Items]      
Discount rate percentage 17.70% 17.30%  
Cash Flow Hedging [Member]      
Schedule of Equity Method Investments [Line Items]      
Number of instruments terminated | Instrument     1
Notional amount | $     $ 26.3
Lightfoot Capital Partners LP [Member]      
Schedule of Equity Method Investments [Line Items]      
Receiving and regasification terminal, volume per day (bcf/d) | Bcf / d 1.5    
Lightfoot Capital Partners LP [Member] | Arc Logistics Partners LP [Member]      
Schedule of Equity Method Investments [Line Items]      
Limited partner interest 40.00%