Revenue (Disaggregation Of Revenues, By Type) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Total revenues	$ 336,072	$ 356,585	$ 367,438	$ 365,274	$ 389,447	$ 378,400	$ 356,901	$ 354,109	$ 1,425,369	$ 1,478,857	$ 1,305,529
Drilling Products And Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues									411,573	383,719	293,690
Production Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues									405,830	418,525	372,781
Technical Solutions [Member]
Disaggregation of Revenue [Line Items]
Total revenues									266,669	270,365	272,422
Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues									885,252	933,029	868,211
Services [Member] | Drilling Products And Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues									69,958	54,997
Services [Member] | Onshore Completion and Workover Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues									303,542	364,500
Services [Member] | Production Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues									348,168	352,590
Services [Member] | Technical Solutions [Member]
Disaggregation of Revenue [Line Items]
Total revenues									163,584	160,942
Rentals [Member]
Disaggregation of Revenue [Line Items]
Total revenues									376,247	380,296	279,936
Rentals [Member] | Drilling Products And Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues									291,975	281,750
Rentals [Member] | Onshore Completion and Workover Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues									37,755	41,748
Rentals [Member] | Production Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues									32,402	36,568
Rentals [Member] | Technical Solutions [Member]
Disaggregation of Revenue [Line Items]
Total revenues									14,115	20,230
Product Sales [Member]
Disaggregation of Revenue [Line Items]
Total revenues									163,870	165,532	$ 157,382
Product Sales [Member] | Drilling Products And Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues									49,640	46,972
Product Sales [Member] | Production Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues									25,260	29,367
Product Sales [Member] | Technical Solutions [Member]
Disaggregation of Revenue [Line Items]
Total revenues									$ 88,970	$ 89,193