Segment Information (Schedule Of Identifiable Assets) (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Feb. 02, 2021	Dec. 31, 2020
Segment Reporting Information [Line Items]
Identifiable Assets	$ 1,255,783	$ 1,456,804	$ 1,501,079
Rentals [Member]
Segment Reporting Information [Line Items]
Identifiable Assets	386,220
Well Services [Member]
Segment Reporting Information [Line Items]
Identifiable Assets	697,291
Drilling Products and Services [Member]
Segment Reporting Information [Line Items]
Identifiable Assets			557,469
Onshore Completion and Workover Services [Member]
Segment Reporting Information [Line Items]
Identifiable Assets			183,065
Production Services [Member]
Segment Reporting Information [Line Items]
Identifiable Assets			368,185
Technical Solutions [Member]
Segment Reporting Information [Line Items]
Identifiable Assets			260,339
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Identifiable Assets	$ 172,272		$ 132,021