Quarterly report pursuant to Section 13 or 15(d)

Contingencies - Additional Information (Details)

v2.4.1.9
Contingencies - Additional Information (Details) (USD $)
 1 Months Ended 3 Months Ended
Jan. 31, 2014
Mar. 31, 2014
Mar. 31, 2015
Dec. 15, 2014
Dec. 31, 2010
Loss Contingencies [Line Items]          
Underpayment of royalties $ 30,000wti_UnderPaymentOfRoyalty        
Under payment percentage of total royalty payments 0.0045%wti_UnderPaymentOfRoyaltyPercentage        
Statutory fine payment relative to underpayment   2,300,000us-gaap_LossContingencyDamagesAwardedValue      
Loss contingency, range of possible loss, minimum       0us-gaap_LossContingencyRangeOfPossibleLossMinimum  
Loss contingency, range of possible loss, maximum       32,000,000us-gaap_LossContingencyRangeOfPossibleLossMaximum  
Insurance claims submitted for removal-of-wreck expenses     42,000,000wti_ClaimsSubmittedRelatedToRemovalOfWreckExpenses    
Notified disallowed amount in reductions taken by ONRR         4,700,000us-gaap_GainContingencyUnrecordedAmount
Liberty Mutual Insurance Co          
Loss Contingencies [Line Items]          
Insurance claims received     5,000,000us-gaap_LossContingencyRelatedReceivableCarryingValueReceipts
/ dei_LegalEntityAxis
= wti_LibertyMutualInsuranceCoMember 		   
Revised estimate          
Loss Contingencies [Line Items]          
Insurance claims receivable     30,000,000us-gaap_LossContingencyReceivable
/ us-gaap_StatementScenarioAxis
= us-gaap_ScenarioForecastMember 		   
Comprehensive General Liability policy          
Loss Contingencies [Line Items]          
Insurance claims received     1,000,000us-gaap_LossContingencyRelatedReceivableCarryingValueReceipts
/ us-gaap_ScheduleOfMalpracticeInsuranceTypeAndTierIdentifierAxis
= us-gaap_GeneralLiabilityMember 		   
Energy Package          
Loss Contingencies [Line Items]          
Insurance claims received     1,000,000us-gaap_LossContingencyRelatedReceivableCarryingValueReceipts
/ us-gaap_ScheduleOfMalpracticeInsuranceTypeAndTierIdentifierAxis
= wti_EnergyPackageMember 		   
Starr Marine          
Loss Contingencies [Line Items]          
Insurance claims received     $ 5,000,000us-gaap_LossContingencyRelatedReceivableCarryingValueReceipts
/ us-gaap_ScheduleOfMalpracticeInsuranceTypeAndTierIdentifierAxis
= wti_StarrMarineMember