Segment Information (Schedule Of Identifiable Assets) (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Segment Reporting Information [Line Items]
Identifiable Assets	$ 2,146,297	$ 2,215,962
Drilling Products and Services [Member]
Segment Reporting Information [Line Items]
Identifiable Assets	633,898	587,264
Onshore Completion and Workover Services [Member]
Segment Reporting Information [Line Items]
Identifiable Assets	684,551	808,037
Production Services [Member]
Segment Reporting Information [Line Items]
Identifiable Assets	398,441	434,430
Technical Solutions [Member]
Segment Reporting Information [Line Items]
Identifiable Assets	360,056	340,161
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Identifiable Assets	$ 69,351	$ 46,070