Derivative Instruments And Hedging Activities Notional Contracts by Derivative Type (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Jun. 30, 2014
economic hedges by derivative type [Line Items]
Available-for-sale Securities, Change in Net Unrealized Holding Gain (Loss) before Taxes	$ 3.8
Commodity WCS Spread [Member]
economic hedges by derivative type [Line Items]
Portion of Future Oil and Gas Production Being Hedged	3,220,000
Natural Gas - long [Member]
economic hedges by derivative type [Line Items]
Portion Of Future Gas Production Being Hedged	33,600,000
Portion of future gas production hedged for price risk	33,600,000
Natural Gas - Short [Member]
economic hedges by derivative type [Line Items]
Portion Of Future Gas Production Being Hedged	33,600,000
Commodity WTI short [Member]
economic hedges by derivative type [Line Items]
Portion of Future Oil and Gas Production Being Hedged	2,935,000
WTI Crude Oil [Member]
economic hedges by derivative type [Line Items]
Portion of oil and gas production hedged for price risk	18,456,000
Ultra Low Sulfur Diesel Member
economic hedges by derivative type [Line Items]
Portion of oil and gas production hedged for price risk	11,832,000
Sub octane gasoline - short [Member]
economic hedges by derivative type [Line Items]
Portion of oil and gas production hedged for price risk	6,624,000
Gasoline And Diesel Member
economic hedges by derivative type [Line Items]
Portion of oil and gas production hedged for price risk	100,000
Maturing in next twelve months [Member] | Commodity WCS Spread [Member]
economic hedges by derivative type [Line Items]
Portion of Future Oil and Gas Production Being Hedged	3,220,000
Maturing in next twelve months [Member] | Natural Gas - long [Member]
economic hedges by derivative type [Line Items]
Portion Of Future Gas Production Being Hedged	4,800,000
Portion of future gas production hedged for price risk	4,800,000
Maturing in next twelve months [Member] | Natural Gas - Short [Member]
economic hedges by derivative type [Line Items]
Portion Of Future Gas Production Being Hedged	4,800,000
Maturing in next twelve months [Member] | Commodity WTI short [Member]
economic hedges by derivative type [Line Items]
Portion of Future Oil and Gas Production Being Hedged	2,935,000
Maturing in next twelve months [Member] | WTI Crude Oil [Member]
economic hedges by derivative type [Line Items]
Portion of oil and gas production hedged for price risk	14,076,000
Maturing in next twelve months [Member] | Ultra Low Sulfur Diesel Member
economic hedges by derivative type [Line Items]
Portion of oil and gas production hedged for price risk	7,452,000
Maturing in next twelve months [Member] | Sub octane gasoline - short [Member]
economic hedges by derivative type [Line Items]
Portion of oil and gas production hedged for price risk	6,624,000
Maturing in next twelve months [Member] | Gasoline And Diesel Member
economic hedges by derivative type [Line Items]
Portion of oil and gas production hedged for price risk	100,000
Maturing in year two [Member] | Natural Gas - long [Member]
economic hedges by derivative type [Line Items]
Portion Of Future Gas Production Being Hedged	9,600,000
Portion of future gas production hedged for price risk	9,600,000
Maturing in year two [Member] | Natural Gas - Short [Member]
economic hedges by derivative type [Line Items]
Portion Of Future Gas Production Being Hedged	9,600,000
Maturing in year two [Member] | WTI Crude Oil [Member]
economic hedges by derivative type [Line Items]
Portion of oil and gas production hedged for price risk	4,380,000
Maturing in year two [Member] | Ultra Low Sulfur Diesel Member
economic hedges by derivative type [Line Items]
Portion of oil and gas production hedged for price risk	4,380,000
Maturing in year three [Member] | Natural Gas - long [Member]
economic hedges by derivative type [Line Items]
Portion Of Future Gas Production Being Hedged	9,600,000
Portion of future gas production hedged for price risk	9,600,000
Maturing in year three [Member] | Natural Gas - Short [Member]
economic hedges by derivative type [Line Items]
Portion Of Future Gas Production Being Hedged	9,600,000
Maturing in year four [Member] | Natural Gas - long [Member]
economic hedges by derivative type [Line Items]
Portion Of Future Gas Production Being Hedged	9,600,000
Portion of future gas production hedged for price risk	9,600,000
Maturing in year four [Member] | Natural Gas - Short [Member]
economic hedges by derivative type [Line Items]
Portion Of Future Gas Production Being Hedged	9,600,000