Segment Information (Schedule Of Identifiable Assets) (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Identifiable Assets	$ 2,123,751	$ 2,215,962
Drilling Products and Services [Member]
Segment Reporting Information [Line Items]
Identifiable Assets	663,515	587,264
Onshore Completion and Workover Services [Member]
Segment Reporting Information [Line Items]
Identifiable Assets	607,947	808,037
Production Services [Member]
Segment Reporting Information [Line Items]
Identifiable Assets	420,208	434,430
Technical Solutions [Member]
Segment Reporting Information [Line Items]
Identifiable Assets	361,434	340,161
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Identifiable Assets	$ 70,647	$ 46,070