Commitments (Narrative) (Details)	Dec. 31, 2016 $ / bbl	Sep. 30, 2015 MMcf / D CAD / Mcf
Natural Gas [Member] | 2015 Deliveries [Member]
Commitments and Contingencies Disclosure [Line Items]
Notional amount, per day		65
Swap price | CAD / Mcf		4.13
Natural Gas [Member] | 2016 Deliveries [Member]
Commitments and Contingencies Disclosure [Line Items]
Notional amount, per day		59
Swap price | CAD / Mcf		3.19
Scenario, Forecast [Member]
Commitments and Contingencies Disclosure [Line Items]
Swap price | $ / bbl	52.01