Revenue (Disaggregation Of Revenues, By Type) (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
Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	180,236	239,274
Services [Member] | Drilling Products and Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	14,576	18,959
Services [Member] | Onshore Completion and Workover Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	54,104	92,516
Services [Member] | Production Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	82,794	87,994
Services [Member] | Technical Solutions [Member]
Disaggregation of Revenue [Line Items]
Total revenues	28,762	39,805
Rentals [Member]
Disaggregation of Revenue [Line Items]
Total revenues	100,105	91,036
Rentals [Member] | Drilling Products and Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	77,829	69,958
Rentals [Member] | Onshore Completion and Workover Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	7,114	10,620
Rentals [Member] | Production Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	8,788	8,602
Rentals [Member] | Technical Solutions [Member]
Disaggregation of Revenue [Line Items]
Total revenues	6,374	1,856
Product Sales [Member]
Disaggregation of Revenue [Line Items]
Total revenues	41,156	34,964
Product Sales [Member] | Drilling Products and Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	11,588	12,162
Product Sales [Member] | Production Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	9,922	6,854
Product Sales [Member] | Technical Solutions [Member]
Disaggregation of Revenue [Line Items]
Total revenues	$ 19,646	$ 15,948