Segment Information (Schedule Of Identifiable Assets) (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Identifiable Assets	$ 1,830,891	$ 1,993,230
Drilling Products and Services [Member]
Segment Reporting Information [Line Items]
Identifiable Assets	681,004	659,621
Onshore Completion and Workover Services [Member]
Segment Reporting Information [Line Items]
Identifiable Assets	353,331	467,697
Production Services [Member]
Segment Reporting Information [Line Items]
Identifiable Assets	422,673	421,848
Technical Solutions [Member]
Segment Reporting Information [Line Items]
Identifiable Assets	309,719	377,627
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Identifiable Assets	$ 64,164	$ 66,437