Annual report pursuant to Section 13 and 15(d)

Share-Based and Cash-Based Incentive Compensation - Summary of Incentive Compensation Expense (Details)

v2.4.1.9
Share-Based and Cash-Based Incentive Compensation - Summary of Incentive Compensation Expense (Details) (USD $)
In Thousands, unless otherwise specified
 12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]      
Share-based compensation charged to operating income $ 14,744us-gaap_ShareBasedCompensation $ 11,525us-gaap_ShareBasedCompensation $ 12,398us-gaap_ShareBasedCompensation
Total charged to operating income 24,979wti_IncentiveCompensationChargedToOperatingIncomeLoss 23,824wti_IncentiveCompensationChargedToOperatingIncomeLoss 22,743wti_IncentiveCompensationChargedToOperatingIncomeLoss
General and Administrative      
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]      
Share-based compensation charged to operating income 14,744us-gaap_ShareBasedCompensation
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_GeneralAndAdministrativeExpenseMember 		[1] 11,525us-gaap_ShareBasedCompensation
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_GeneralAndAdministrativeExpenseMember 		[1] 12,398us-gaap_ShareBasedCompensation
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_GeneralAndAdministrativeExpenseMember 		[1]
Cash-based incentive compensation charged to operating income 6,950wti_CashBasedIncentiveCompensationChargedToOperatingIncomeLoss
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_GeneralAndAdministrativeExpenseMember 		[1] 8,817wti_CashBasedIncentiveCompensationChargedToOperatingIncomeLoss
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_GeneralAndAdministrativeExpenseMember 		[1] 6,558wti_CashBasedIncentiveCompensationChargedToOperatingIncomeLoss
/ us-gaap_IncomeStatementLocationAxis
= us-gaap_GeneralAndAdministrativeExpenseMember 		[1]
Lease Operating Expense      
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]      
Cash-based incentive compensation charged to operating income $ 3,285wti_CashBasedIncentiveCompensationChargedToOperatingIncomeLoss
/ us-gaap_IncomeStatementLocationAxis
= wti_LeaseOperatingExpenseMember 		$ 3,482wti_CashBasedIncentiveCompensationChargedToOperatingIncomeLoss
/ us-gaap_IncomeStatementLocationAxis
= wti_LeaseOperatingExpenseMember 		$ 3,787wti_CashBasedIncentiveCompensationChargedToOperatingIncomeLoss
/ us-gaap_IncomeStatementLocationAxis
= wti_LeaseOperatingExpenseMember
[1] Reclassified $0.7 million from cash-based incentive compensation expense to share-based compensation expense in 2014 related to the CEO’s 2013 award.