Revenue (Disaggregation Of Revenues, By Geography) (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation of Revenue [Line Items]
Total revenues	$ 166,928	$ 356,600	$ 356,585	$ 672,278	$ 1,089,297
Drilling Products and Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	56,001		111,185	227,344	312,946
Onshore Completion and Workover Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	21,559		75,973	103,957	273,727
Production Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	56,355		98,787	212,352	305,239
Technical Solutions [Member]
Disaggregation of Revenue [Line Items]
Total revenues	33,013		70,640	128,625	197,385
U.S. Land [Member]
Disaggregation of Revenue [Line Items]
Total revenues	46,488		162,466	236,147	560,484
U.S. Land [Member] | Drilling Products and Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	10,458		46,590	66,652	142,073
U.S. Land [Member] | Onshore Completion and Workover Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	21,559		75,973	103,957	273,727
U.S. Land [Member] | Production Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	9,777		32,620	51,541	112,095
U.S. Land [Member] | Technical Solutions [Member]
Disaggregation of Revenue [Line Items]
Total revenues	4,694		7,283	13,997	32,589
U.S. Offshore [Member]
Disaggregation of Revenue [Line Items]
Total revenues	48,612		92,961	187,229	245,220
U.S. Offshore [Member] | Drilling Products and Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	26,242		33,895	92,053	91,048
U.S. Offshore [Member] | Production Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	6,630		18,295	24,292	58,977
U.S. Offshore [Member] | Technical Solutions [Member]
Disaggregation of Revenue [Line Items]
Total revenues	15,740		40,771	70,884	95,195
International [Member]
Disaggregation of Revenue [Line Items]
Total revenues	71,828		101,158	248,902	283,593
International [Member] | Drilling Products and Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	19,301		30,700	68,639	79,825
International [Member] | Production Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	39,948		47,872	136,519	134,167
International [Member] | Technical Solutions [Member]
Disaggregation of Revenue [Line Items]
Total revenues	$ 12,579		$ 22,586	$ 43,744	$ 69,601