Revenue (Disaggregation Of Revenues, By Geography) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Disaggregation of Revenue [Line Items]
Total revenues	$ 321,497	$ 365,274
Drilling Products and Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	103,993	101,079
Onshore Completion and Workover Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	61,218	103,136
Production Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	101,504	103,450
Technical Solutions [Member]
Disaggregation of Revenue [Line Items]
Total revenues	54,782	57,609
U.S. Land [Member]
Disaggregation of Revenue [Line Items]
Total revenues	134,678	203,939
U.S. Land [Member] | Drilling Products and Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	36,656	48,217
U.S. Land [Member] | Onshore Completion and Workover Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	61,218	103,136
U.S. Land [Member] | Production Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	30,667	40,666
U.S. Land [Member] | Technical Solutions [Member]
Disaggregation of Revenue [Line Items]
Total revenues	6,137	11,920
U.S. Offshore [Member]
Disaggregation of Revenue [Line Items]
Total revenues	80,056	69,272
U.S. Offshore [Member] | Drilling Products and Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	37,224	29,067
U.S. Offshore [Member] | Production Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	11,299	19,272
U.S. Offshore [Member] | Technical Solutions [Member]
Disaggregation of Revenue [Line Items]
Total revenues	31,533	20,933
International [Member]
Disaggregation of Revenue [Line Items]
Total revenues	106,763	92,063
International [Member] | Drilling Products and Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	30,113	23,795
International [Member] | Production Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	59,538	43,512
International [Member] | Technical Solutions [Member]
Disaggregation of Revenue [Line Items]
Total revenues	$ 17,112	$ 24,756