Note 6 - Derivative Financial Instruments - Cash Receipts on Commodity Derivative Contract Settlements (Details) - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019
Cash receipts on derivative settlements, net	$ 42,028	$ 17,583

The cash inflow (outflow) from derivative instruments during the period, which are classified as operating activities, excluding those designated as hedging instruments.

No definition available.

Name:	wti_ProceedsFromPaymentsForDerivativeInstrumentOperatingActivities
Namespace Prefix:	wti_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration