Annual report pursuant to Section 13 and 15(d)

Significant Accounting Policies - Additional Information (Details)

v2.4.1.9
Significant Accounting Policies - Additional Information (Details) (USD $)
3 Months Ended 12 Months Ended
Dec. 31, 2013
MMcf
Dec. 31, 2014
Dec. 31, 2013
MMcf
Dec. 31, 2012
Significant Accounting Policies [Line Items]        
Increase in natural gas production volumes 2,600wti_IncreaseInProduction   1,900wti_IncreaseInProduction  
Natural gas imbalances $ 6,400,000us-gaap_GasImbalanceAssetLiability $ 6,400,000us-gaap_GasImbalanceAssetLiability $ 6,400,000us-gaap_GasImbalanceAssetLiability  
Percentage of discount from proved reserves   10.00%wti_PercentageOfDiscountFromProvedReserves    
Ceiling test impairment   0us-gaap_ImpairmentOfOilAndGasProperties 0us-gaap_ImpairmentOfOilAndGasProperties 0us-gaap_ImpairmentOfOilAndGasProperties
Proved undeveloped reserves classification period to be drilled   5 years    
Goodwill, acquired during period   0us-gaap_GoodwillAcquiredDuringPeriod 0us-gaap_GoodwillAcquiredDuringPeriod 0us-gaap_GoodwillAcquiredDuringPeriod
Payments received related to break-up fee and termination of certain purchase and sale agreement     9,200,000us-gaap_GainLossOnContractTermination  
Third-party expenses related to the cancelled transaction     100,000us-gaap_OtherExpenses  
Fixtures and Non-Oil and Natural Gas Property and Equipment | Minimum        
Significant Accounting Policies [Line Items]        
Estimated useful lives   5 years    
Fixtures and Non-Oil and Natural Gas Property and Equipment | Maximum        
Significant Accounting Policies [Line Items]        
Estimated useful lives   7 years    
Natural Gas        
Significant Accounting Policies [Line Items]        
Adjustment to depreciation, depletion, amortization and accretion 7,100,000wti_AdjustmentToDepreciationDepletionAmortization
/ us-gaap_ReserveQuantitiesByTypeOfReserveAxis
= us-gaap_NaturalGasReservesMember
5,000,000wti_AdjustmentToDepreciationDepletionAmortization
/ us-gaap_ReserveQuantitiesByTypeOfReserveAxis
= us-gaap_NaturalGasReservesMember
   
Reduction in net income $ 4,600,000wti_ReductionInNetIncome
/ us-gaap_ReserveQuantitiesByTypeOfReserveAxis
= us-gaap_NaturalGasReservesMember
$ 3,200,000wti_ReductionInNetIncome
/ us-gaap_ReserveQuantitiesByTypeOfReserveAxis
= us-gaap_NaturalGasReservesMember