Derivative Instruments And Hedging Activities Notional Contracts by Derivative Type (Details) - 3 months ended Mar. 31, 2019	XPT ( ) MMBTU bbl	USD ($)
Commodity Contract [Member]
Economic hedges by derivative type [Line Items]
Derivative, Notional Amount |	41,147
Designated as Hedging Instrument [Member] | Natural Gas [Member]
Economic hedges by derivative type [Line Items]
Derivative, Nonmonetary Notional Amount, Energy Measure | MMBTU	4,950,000
Designated as Hedging Instrument [Member] | Price Risk Derivative [Member]
Economic hedges by derivative type [Line Items]
Price Risk Fair Value Hedge Derivative, at Fair Value, Net	8,333,000
Designated as Hedging Instrument [Member] | Maturing in Next Twelve Months [Member] | Natural Gas [Member]
Economic hedges by derivative type [Line Items]
Derivative, Nonmonetary Notional Amount, Energy Measure | MMBTU	1,350,000
Designated as Hedging Instrument [Member] | Maturing in Next Twelve Months [Member] | Price Risk Derivative [Member]
Economic hedges by derivative type [Line Items]
Price Risk Fair Value Hedge Derivative, at Fair Value, Net	3,575,000
Designated as Hedging Instrument [Member] | Maturing in Year Two [Member] | Natural Gas [Member]
Economic hedges by derivative type [Line Items]
Derivative, Nonmonetary Notional Amount, Energy Measure | MMBTU	1,800,000
Designated as Hedging Instrument [Member] | Maturing in Year Two [Member] | Price Risk Derivative [Member]
Economic hedges by derivative type [Line Items]
Price Risk Fair Value Hedge Derivative, at Fair Value, Net	4,758,000
Designated as Hedging Instrument [Member] | Maturing in Year Three [Member] | Natural Gas [Member]
Economic hedges by derivative type [Line Items]
Derivative, Nonmonetary Notional Amount, Energy Measure | MMBTU	1,800,000
Designated as Hedging Instrument [Member] | Maturing in Year Three [Member] | Price Risk Derivative [Member]
Economic hedges by derivative type [Line Items]
Price Risk Fair Value Hedge Derivative, at Fair Value, Net	0
Not Designated as Hedging Instrument [Member]
Economic hedges by derivative type [Line Items]
Foreign Currency Derivative Instruments Not Designated as Hedging Instruments at Fair Value, Net | $		$ 440,629,812
Not Designated as Hedging Instrument [Member] | Commodity Contract [Member]
Economic hedges by derivative type [Line Items]
Price Risk Fair Value Hedge Derivative, at Fair Value, Net	395,000
Not Designated as Hedging Instrument [Member] | Maturing in Next Twelve Months [Member]
Economic hedges by derivative type [Line Items]
Foreign Currency Derivative Instruments Not Designated as Hedging Instruments at Fair Value, Net | $		$ 440,629,812
Not Designated as Hedging Instrument [Member] | Maturing in Next Twelve Months [Member] | Commodity Contract [Member]
Economic hedges by derivative type [Line Items]
Price Risk Fair Value Hedge Derivative, at Fair Value, Net	395,000
Derivative, Notional Amount |	41,147