Derivatives (Cash Flow Hedges Outstanding) (Details) (Apr'13 - Dec'13 [Member], Designated as Hedging Instrument [Member])	3 Months Ended
	Mar. 31, 2013 bbl
Swap [Member] | WTI - NYMEX [Member] | Crude Oil [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Cash Flow Hedge Derivative Instrument Weighted Average Fixed Price For Swaps	99.71
Hedged Volume (in Bbl/day)	5,500
Swap [Member] | WTI - NYMEX [Member] | Crude Oil [Member] | Start [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Commodity Derivatives Term	Apr'13
Swap [Member] | WTI - NYMEX [Member] | Crude Oil [Member] | End [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Commodity Derivatives Term	Dec'13
Swap [Member] | IF - NYMEX (HH) [Member] | Natural Gas [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Cash Flow Hedge Derivative Instrument Weighted Average Fixed Price For Swaps	3.56
Hedged Volume (MMBtu/day)	60,000
Swap [Member] | IF - NYMEX (HH) [Member] | Natural Gas [Member] | Start [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Commodity Derivatives Term	Apr'13
Swap [Member] | IF - NYMEX (HH) [Member] | Natural Gas [Member] | End [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Commodity Derivatives Term	Dec'13
Collar [Member] | IF - NYMEX (HH) [Member] | Natural Gas [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Hedged Volume (MMBtu/day)	20,000
Collar [Member] | IF - NYMEX (HH) [Member] | Natural Gas [Member] | Start [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Cash Flow Hedge Derivative Instrument Weighted Average Fixed Price For Swaps	3.25
Commodity Derivatives Term	Apr'13
Collar [Member] | IF - NYMEX (HH) [Member] | Natural Gas [Member] | End [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Cash Flow Hedge Derivative Instrument Weighted Average Fixed Price For Swaps	3.72
Commodity Derivatives Term	Dec'13