Revenue (Disaggregation Of Revenues, By Geography) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Disaggregation of Revenue [Line Items]
Total revenues	$ 425,717	$ 573,068	$ 1,329,208	$ 1,590,934
Drilling Products and Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	111,185	99,184	312,946	278,419
Onshore Completion and Workover Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	145,105	294,869	513,638	802,600
Production Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	98,787	105,870	305,239	308,591
Technical Solutions [Member]
Disaggregation of Revenue [Line Items]
Total revenues	70,640	73,145	197,385	201,324
U.S. Land [Member]
Disaggregation of Revenue [Line Items]
Total revenues	231,598	396,785	800,395	1,103,719
U.S. Land [Member] | Drilling Products and Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	46,590	45,605	142,073	129,716
U.S. Land [Member] | Onshore Completion and Workover Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	145,105	294,869	513,638	802,600
U.S. Land [Member] | Production Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	32,620	47,858	112,095	148,259
U.S. Land [Member] | Technical Solutions [Member]
Disaggregation of Revenue [Line Items]
Total revenues	7,283	8,453	32,589	23,144
U.S. Offshore [Member]
Disaggregation of Revenue [Line Items]
Total revenues	92,961	90,127	245,220	238,406
U.S. Offshore [Member] | Drilling Products and Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	33,895	26,065	91,048	70,315
U.S. Offshore [Member] | Production Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	18,295	16,776	58,977	47,910
U.S. Offshore [Member] | Technical Solutions [Member]
Disaggregation of Revenue [Line Items]
Total revenues	40,771	47,286	95,195	120,181
International [Member]
Disaggregation of Revenue [Line Items]
Total revenues	101,158	86,156	283,593	248,809
International [Member] | Drilling Products and Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	30,700	27,514	79,825	78,388
International [Member] | Production Services [Member]
Disaggregation of Revenue [Line Items]
Total revenues	47,872	41,236	134,167	112,422
International [Member] | Technical Solutions [Member]
Disaggregation of Revenue [Line Items]
Total revenues	$ 22,586	$ 17,406	$ 69,601	$ 57,999