Revenue (Disaggregation Of Revenues, By Geography) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Total revenues	$ 436,315	$ 535,548	$ 903,491	$ 1,017,866
Drilling Products and Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	100,682	94,033	201,761	179,235
Onshore Completion and Workover Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	163,495	276,242	368,533	507,731
Production Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	103,002	102,004	206,452	202,721
Technical Solutions [Member]
Disaggregation of Revenue [Line Items]
Total revenues	69,136	63,269	126,745	128,179
U.S. Land [Member]
Disaggregation of Revenue [Line Items]
Total revenues	262,955	375,438	568,798	706,934
U.S. Land [Member] | Drilling Products and Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	47,267	43,394	95,483	84,111
U.S. Land [Member] | Onshore Completion and Workover Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	163,495	276,242	368,533	507,731
U.S. Land [Member] | Production Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	38,808	47,944	79,475	100,401
U.S. Land [Member] | Technical Solutions [Member]
Disaggregation of Revenue [Line Items]
Total revenues	13,385	7,858	25,307	14,691
U.S. Offshore [Member]
Disaggregation of Revenue [Line Items]
Total revenues	82,987	72,228	152,259	148,279
U.S. Offshore [Member] | Drilling Products and Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	28,085	23,261	57,153	44,250
U.S. Offshore [Member] | Production Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	21,410	13,634	40,682	31,134
U.S. Offshore [Member] | Technical Solutions [Member]
Disaggregation of Revenue [Line Items]
Total revenues	33,492	35,333	54,424	72,895
International [Member]
Disaggregation of Revenue [Line Items]
Total revenues	90,373	87,882	182,434	162,653
International [Member] | Drilling Products and Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	25,330	27,378	49,125	50,874
International [Member] | Production Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	42,784	40,426	86,295	71,186
International [Member] | Technical Solutions [Member]
Disaggregation of Revenue [Line Items]
Total revenues	$ 22,259	$ 20,078	$ 47,014	$ 40,593