Commitments (Narrative) (Details) - Natural Gas [Member]	Oct. 31, 2016 MMcf / d CAD / Mcf	Sep. 30, 2016 MMcf / D MMcf / d CAD / Mcf
2016 Deliveries [Member]
Commitments and Contingencies Disclosure [Line Items]
Notional amount, per day | MMcf / D		99
Swap price (per share)		3.00
January 2017 Through December 2017 Deliveries [Member]
Commitments and Contingencies Disclosure [Line Items]
Notional amount, per day | MMcf / d		79
Swap price (per share)		2.83
January 2018 Through December 2020 Deliveries [Member]
Commitments and Contingencies Disclosure [Line Items]
Notional amount, per day | MMcf / D		59
Swap price (per share)		2.81
Subsequent Event [Member] | January 2017 Through December 2020 Deliveries, Contract 2 [Member]
Commitments and Contingencies Disclosure [Line Items]
Notional amount, per day | MMcf / d	20
Swap price (per share)	3.12