Annual report pursuant to Section 13 and 15(d)

Acquisitions and Divestitures - Summary of Proforma Financial Information for Acquisition (Details)

v2.4.1.9
Acquisitions and Divestitures - Summary of Proforma Financial Information for Acquisition (Details) (USD $)
In Thousands, except Per Share data, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Woodside Properties      
Business Acquisition [Line Items]      
Revenue $ 971,595us-gaap_BusinessAcquisitionsProFormaRevenue
/ us-gaap_BusinessAcquisitionAxis
= wti_WoodsidePropertiesMember
$ 1,047,037us-gaap_BusinessAcquisitionsProFormaRevenue
/ us-gaap_BusinessAcquisitionAxis
= wti_WoodsidePropertiesMember
 
Net income (loss) (5,495)us-gaap_BusinessAcquisitionsProFormaNetIncomeLoss
/ us-gaap_BusinessAcquisitionAxis
= wti_WoodsidePropertiesMember
71,432us-gaap_BusinessAcquisitionsProFormaNetIncomeLoss
/ us-gaap_BusinessAcquisitionAxis
= wti_WoodsidePropertiesMember
 
Basic and diluted earnings (loss) per common share $ (0.08)us-gaap_BusinessAcquisitionProFormaEarningsPerShareDiluted
/ us-gaap_BusinessAcquisitionAxis
= wti_WoodsidePropertiesMember
$ 0.94us-gaap_BusinessAcquisitionProFormaEarningsPerShareDiluted
/ us-gaap_BusinessAcquisitionAxis
= wti_WoodsidePropertiesMember
 
Callon Properties      
Business Acquisition [Line Items]      
Revenue   1,018,118us-gaap_BusinessAcquisitionsProFormaRevenue
/ us-gaap_BusinessAcquisitionAxis
= wti_CallonPropertiesMember
923,050us-gaap_BusinessAcquisitionsProFormaRevenue
/ us-gaap_BusinessAcquisitionAxis
= wti_CallonPropertiesMember
Net income (loss)   59,015us-gaap_BusinessAcquisitionsProFormaNetIncomeLoss
/ us-gaap_BusinessAcquisitionAxis
= wti_CallonPropertiesMember
85,310us-gaap_BusinessAcquisitionsProFormaNetIncomeLoss
/ us-gaap_BusinessAcquisitionAxis
= wti_CallonPropertiesMember
Basic and diluted earnings (loss) per common share   $ 0.78us-gaap_BusinessAcquisitionProFormaEarningsPerShareDiluted
/ us-gaap_BusinessAcquisitionAxis
= wti_CallonPropertiesMember
$ 1.12us-gaap_BusinessAcquisitionProFormaEarningsPerShareDiluted
/ us-gaap_BusinessAcquisitionAxis
= wti_CallonPropertiesMember
Newfield Properties      
Business Acquisition [Line Items]      
Revenue     980,196us-gaap_BusinessAcquisitionsProFormaRevenue
/ us-gaap_BusinessAcquisitionAxis
= wti_NewfieldPropertiesMember
Net income (loss)     $ 77,036us-gaap_BusinessAcquisitionsProFormaNetIncomeLoss
/ us-gaap_BusinessAcquisitionAxis
= wti_NewfieldPropertiesMember
Basic and diluted earnings (loss) per common share     $ 1.01us-gaap_BusinessAcquisitionProFormaEarningsPerShareDiluted
/ us-gaap_BusinessAcquisitionAxis
= wti_NewfieldPropertiesMember