Segment Information (Schedule Of Identifiable Assets) (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Identifiable Assets	$ 1,574,246	$ 1,993,230
Drilling Products and Services [Member]
Segment Reporting Information [Line Items]
Identifiable Assets	591,152	659,621
Onshore Completion and Workover Services [Member]
Segment Reporting Information [Line Items]
Identifiable Assets	200,101	467,697
Production Services [Member]
Segment Reporting Information [Line Items]
Identifiable Assets	367,944	421,848
Technical Solutions [Member]
Segment Reporting Information [Line Items]
Identifiable Assets	272,893	377,627
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Identifiable Assets	$ 142,156	$ 66,437