CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating revenues:
Oil and natural gas		$ 24,931,000	$ 50,196,000	$ 57,257,000
Total operating revenues		1,891,277,000	3,182,291,000	2,716,034,000
Operating costs and expenses:
Contract drilling		608,848,000	1,066,659,000	968,754,000
Pressure pumping		612,021,000	1,036,310,000	744,243,000
Oil and natural gas		11,500,000	13,102,000	12,909,000
Depreciation, depletion, amortization and impairment		864,759,000	718,730,000	597,469,000
Impairment of goodwill		124,561,000
Selling, general and administrative		87,173,000	80,145,000	73,852,000
Net gain on asset disposals	[1]	(10,613,000)	(15,781,000)	(3,384,000)
Total operating costs and expenses		2,298,249,000	2,899,165,000	2,393,843,000
Operating income (loss)		(406,972,000)	283,126,000	322,191,000
Other income (expense):
Interest income		964,000	979,000	918,000
Interest expense, net of amount capitalized		(36,475,000)	(29,825,000)	(28,359,000)
Other		34,000	3,000	1,691,000
Total other expense		(35,477,000)	(28,843,000)	(25,750,000)
Income (loss) before income taxes		(442,449,000)	254,283,000	296,441,000
Income tax expense (benefit):
Current		(48,090,000)	47,946,000	57,863,000
Deferred		(99,873,000)	43,673,000	50,569,000
Total income tax expense (benefit)		(147,963,000)	91,619,000	108,432,000
Net income (loss)		$ (294,486,000)	$ 162,664,000	$ 188,009,000
Net income (loss) per common share:
Basic		$ (2.00)	$ 1.12	$ 1.29
Diluted		$ (2.00)	$ 1.11	$ 1.28
Weighted average number of common shares outstanding:
Basic		145,416	144,066	144,356
Diluted		145,416	145,376	145,303
Cash dividends per common share		$ 0.40	$ 0.40	$ 0.20
Contract Drilling
Operating revenues:
Oil and gas services		$ 1,153,892,000	$ 1,838,830,000	$ 1,679,611,000
Operating costs and expenses:
Impairment of goodwill		0
Pressure Pumping
Operating revenues:
Oil and gas services		$ 712,454,000	$ 1,293,265,000	$ 979,166,000

[1] Net gains or losses associated with the disposal of assets relate to corporate strategy decisions of the executive management group. Accordingly, the related gains or losses have been separately presented and excluded from the results of specific segments.