Annual report pursuant to Section 13 and 15(d)

Selected Quarterly Financial Data (Parenthetical) (Details)

v2.4.1.9
Selected Quarterly Financial Data (Parenthetical) (Details) (USD $)
In Millions, unless otherwise specified
 3 Months Ended 12 Months Ended
Dec. 31, 2013
MMcf
Dec. 31, 2013
MMcf
Dec. 31, 2014
Quarterly Financial Data [Line Items]      
One-time increase in production 2,600wti_IncreaseInProduction 1,900wti_IncreaseInProduction  
Natural Gas      
Quarterly Financial Data [Line Items]      
Adjustment to depreciation, depletion, amortization and accretion 7.1wti_AdjustmentToDepreciationDepletionAmortization
/ us-gaap_ReserveQuantitiesByTypeOfReserveAxis
= us-gaap_NaturalGasReservesMember 		  $ 5.0wti_AdjustmentToDepreciationDepletionAmortization
/ us-gaap_ReserveQuantitiesByTypeOfReserveAxis
= us-gaap_NaturalGasReservesMember
Reduction in net income 4.6wti_ReductionInNetIncome
/ us-gaap_ReserveQuantitiesByTypeOfReserveAxis
= us-gaap_NaturalGasReservesMember 		  $ 3.2wti_ReductionInNetIncome
/ us-gaap_ReserveQuantitiesByTypeOfReserveAxis
= us-gaap_NaturalGasReservesMember