Revenue (Disaggregation Of Revenues, By Type) (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
Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	344,304	446,812	720,443	846,580
Services [Member] | Drilling Products and Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	28,046	27,461	59,169	51,466
Services [Member] | Onshore Completion and Workover Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	154,395	266,071	348,812	487,418
Services [Member] | Production Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	95,752	93,678	190,600	188,292
Services [Member] | Technical Solutions [Member]
Disaggregation of Revenue [Line Items]
Total revenues	66,111	59,602	121,862	119,404
Rentals [Member]
Disaggregation of Revenue [Line Items]
Total revenues	92,011	88,736	183,048	171,286
Rentals [Member] | Drilling Products and Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	72,636	66,572	142,592	127,769
Rentals [Member] | Onshore Completion and Workover Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	9,100	10,171	19,721	20,313
Rentals [Member] | Production Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	7,250	8,326	15,852	14,429
Rentals [Member] | Technical Solutions [Member]
Disaggregation of Revenue [Line Items]
Total revenues	$ 3,025	$ 3,667	$ 4,883	$ 8,775