Revenue (Disaggregation Of Revenues, By Geography) (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
U.S. Land [Member]
Disaggregation of Revenue [Line Items]
Total revenues									698,305	809,196	670,407
U.S. Land [Member] | Drilling Products And Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues									178,345	176,448	117,856
U.S. Land [Member] | Onshore Completion and Workover Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues									341,297	406,248	366,636
U.S. Land [Member] | Production Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues									138,300	195,363	151,632
U.S. Land [Member] | Technical Solutions [Member]
Disaggregation of Revenue [Line Items]
Total revenues									40,363	31,137	34,283
U.S. Offshore [Member]
Disaggregation of Revenue [Line Items]
Total revenues									340,565	327,874	327,306
U.S. Offshore [Member] | Drilling Products And Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues									125,104	100,855	91,507
U.S. Offshore [Member] | Production Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues									73,610	66,512	74,033
U.S. Offshore [Member] | Technical Solutions [Member]
Disaggregation of Revenue [Line Items]
Total revenues									141,851	160,507	161,766
International [Member]
Disaggregation of Revenue [Line Items]
Total revenues									386,499	341,787	307,816
International [Member] | Drilling Products And Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues									108,124	106,416	84,327
International [Member] | Production Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues									193,920	156,650	147,116
International [Member] | Technical Solutions [Member]
Disaggregation of Revenue [Line Items]
Total revenues									$ 84,455	$ 78,721	$ 76,373