Condensed Consolidated Statements of Operations - USD ($) shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Revenues:
Services	$ 431,874,000	$ 266,093,000	$ 1,170,455,000	$ 873,985,000
Rentals	74,155,000	60,132,000	206,578,000	221,644,000
Total Revenues	506,029,000	326,225,000	1,377,033,000	1,095,629,000
Costs and expenses:
Cost of services (exclusive of depreciation, depletion, amortization and accretion)	340,401,000	223,766,000	959,630,000	703,061,000
Cost of rentals (exclusive of depreciation, depletion, amortization and accretion)	27,878,000	34,402,000	82,437,000	99,081,000
Depreciation, depletion, amortization and accretion - services	92,814,000	100,579,000	281,097,000	312,713,000
Depreciation, depletion, amortization and accretion - rentals	15,937,000	22,729,000	50,054,000	79,304,000
General and administrative expenses	74,372,000	86,743,000	226,573,000	270,467,000
Reduction in value of assets	9,953,000	0	9,953,000	462,461,000
Loss from operations	(55,326,000)	(141,994,000)	(232,711,000)	(831,458,000)
Other income (expense):
Interest expense, net	(29,096,000)	(21,771,000)	(76,679,000)	(68,325,000)
Other income (expense)	(970,000)	3,667,000	(2,477,000)	22,103,000
Loss from continuing operations before income taxes	(85,392,000)	(160,098,000)	(311,867,000)	(877,680,000)
Income taxes	(28,203,000)	(46,185,000)	(102,978,000)	(210,599,000)
Net loss from continuing operations	(57,189,000)	(113,913,000)	(208,889,000)	(667,081,000)
Loss from discontinued operations, net of income tax	(1,860,000)	(4,085,000)	(5,625,000)	(8,577,000)
Net loss	$ (59,049,000)	$ (117,998,000)	$ (214,514,000)	$ (675,658,000)
Basic and diluted:
Net loss from continuing operations	$ (0.37)	$ (0.75)	$ (1.37)	$ (4.40)
Loss from discontinued operations	(0.02)	(0.03)	(0.04)	(0.06)
Net loss	$ (0.39)	$ (0.78)	$ (1.41)	(4.46)
Cash dividends declared per share				$ 0.08
Weighted average common shares used in computing loss per share:
Basic and diluted	153,082	151,707	152,624	151,337