Consolidated Statements of Operations (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Revenues:
Contract drilling	$ 339,636	$ 599,036	$ 1,140,568	$ 1,816,055
Revenues related to reimbursable expenses	9,542	10,706	67,900	47,775
Total revenues	349,178	609,742	1,208,468	1,863,830
Operating expenses:
Contract drilling, excluding depreciation	186,654	277,944	597,831	971,471
Reimbursable expenses	7,965	10,476	51,283	46,904
Depreciation	86,473	118,086	295,729	378,714
General and administrative	15,237	16,888	48,774	50,888
Impairment of assets		2,546	678,145	361,074
Restructuring and separation costs		1,574		8,735
(Gain) loss on disposition of assets	(1,222)	794	(2,265)	19
Total operating expenses	295,107	428,308	1,669,497	1,817,805
Operating income (loss)	54,071	181,434	(461,029)	46,025
Other income (expense):
Interest income	150	629	592	1,796
Interest expense, net of amounts capitalized	(19,032)	(21,350)	(68,704)	(70,800)
Foreign currency transaction (loss) gain	(712)	(1,163)	(7,833)	954
Other, net	269	217	(11,199)	702
Income (loss) before income tax (expense) benefit	34,746	159,767	(548,173)	(21,323)
Income tax (expense) benefit	(20,819)	(23,345)	59,588	(7,578)
Net income (loss)	$ 13,927	$ 136,422	$ (488,585)	$ (28,901)
Earnings (loss) per share, Basic and Diluted	$ 0.10	$ 0.99	$ (3.56)	$ (0.21)
Weighted-average shares outstanding:
Shares of common stock	137,170	137,159	137,167	137,156
Dilutive potential shares of common stock	84	44
Total weighted-average shares outstanding	137,254	137,203	137,167	137,156
Cash dividends declared per share of common stock		$ 0.125		$ 0.375