Annual report pursuant to Section 13 and 15(d)

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

v2.4.1.9
Share-Based and Cash-Based Incentive Compensation - Summary of Incentive Compensation Expense (Parenthetical) (Details) (CEO's 2013 Award, USD $)
In Millions, unless otherwise specified
12 Months Ended
Dec. 31, 2014
CEO's 2013 Award
 
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]  
Reclassification of incentive compensation $ 0.7wti_ReclassificationOfCashBasedIncentiveCompensationToShareBasedCompensation
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