Segment Information (Schedule Of Segment Reporting Information) (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
Segment Reporting Information [Line Items]
Revenues	$ 166,928	$ 356,600	$ 356,585	$ 672,278	$ 1,089,297
Cost of revenues (exclusive of depreciation, depletion, amortization and accretion	116,233		231,927	456,722	701,512
Depreciation, depletion, amortization and accretion	35,172		45,162	113,313	152,776
General and administrative expenses	54,966		60,866	178,543	203,015
Restructuring expense	25,746			27,033
Reduction in value of assets	2,929		9,571	19,451	17,128
Income (loss) from operations	(68,118)		9,059	(122,784)	14,866
Interest income (expense), net	(24,794)		(24,505)	(74,677)	(74,275)
Other income (expense):	(1,399)		(3,353)	(4,810)	(4,476)
Loss from continuing operations before income taxes	(94,311)		(18,799)	(202,271)	(63,885)
Drilling Products and Services [Member]
Segment Reporting Information [Line Items]
Revenues	56,001		111,185	227,344	312,946
Cost of revenues (exclusive of depreciation, depletion, amortization and accretion	23,714		38,663	81,163	118,732
Depreciation, depletion, amortization and accretion	14,424		20,168	48,042	64,684
General and administrative expenses	12,948		14,363	38,388	44,173
Income (loss) from operations	4,915		37,991	59,751	85,357
Loss from continuing operations before income taxes	4,915		37,991	59,751	85,357
Onshore Completion and Workover Services [Member]
Segment Reporting Information [Line Items]
Revenues	21,559		75,973	103,957	273,727
Cost of revenues (exclusive of depreciation, depletion, amortization and accretion	21,943		61,338	98,774	217,115
Depreciation, depletion, amortization and accretion	5,356		6,853	17,183	27,940
General and administrative expenses	3,319		8,144	12,635	24,044
Reduction in value of assets			566		8,123
Income (loss) from operations	(9,059)		(928)	(24,635)	(3,495)
Loss from continuing operations before income taxes	(9,059)		(928)	(24,635)	(3,495)
Production Services [Member]
Segment Reporting Information [Line Items]
Revenues	56,355		98,787	212,352	305,239
Cost of revenues (exclusive of depreciation, depletion, amortization and accretion	46,115		82,556	177,624	240,855
Depreciation, depletion, amortization and accretion	9,584		12,063	30,604	39,375
General and administrative expenses	6,801		2,905	21,232	18,687
Reduction in value of assets			1,997	4,096	1,997
Income (loss) from operations	(6,145)		(734)	(21,204)	4,325
Loss from continuing operations before income taxes	(6,145)		(734)	(21,204)	4,325
Technical Solutions [Member]
Segment Reporting Information [Line Items]
Revenues	33,013		70,640	128,625	197,385
Cost of revenues (exclusive of depreciation, depletion, amortization and accretion	24,461		49,370	99,161	124,810
Depreciation, depletion, amortization and accretion	4,983		4,909	14,663	17,198
General and administrative expenses	9,844		14,935	34,044	46,394
Reduction in value of assets	2,929		7,008	15,355	7,008
Income (loss) from operations	(9,204)		(5,582)	(34,598)	1,975
Interest income (expense), net	1,122		1,051	3,399	3,104
Loss from continuing operations before income taxes	(8,082)		(4,531)	(31,199)	5,079
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Depreciation, depletion, amortization and accretion	825		1,169	2,821	3,579
General and administrative expenses	22,054		20,519	72,244	69,717
Restructuring expense	25,746			27,033
Income (loss) from operations	(48,625)		(21,688)	(102,098)	(73,296)
Interest income (expense), net	(25,916)		(25,556)	(78,076)	(77,379)
Other income (expense):	(1,399)		(3,353)	(4,810)	(4,476)
Loss from continuing operations before income taxes	$ (75,940)		$ (50,597)	$ (184,984)	$ (155,151)