Chapter 11 Proceedings - Debtor-in-Possession Condensed Combined Statement of Operations (Detail) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Revenues:
Total revenues	$ 138,257		$ 254,020	$ 565,630	$ 704,268
Operating expenses:
Depreciation	75,330		88,693	243,208	263,844
General and administrative	12,781		18,830	44,827	51,436
Impairment of assets		$ 774,000		774,028
Restructuring and separation costs	344			17,463
Gain on disposition of assets	(479)		6,340	(4,132)	1,191
Total operating expenses	227,475		326,854	1,584,767	937,729
Operating loss	(89,218)		(72,834)	(1,019,137)	(233,461)
Other income (expense):
Interest income	22		1,317	520	5,664
Interest expense, net of amounts capitalized	(98)		(31,098)	(42,753)	(92,182)
Foreign currency transaction gain	(661)		(77)	(1,458)	(1,883)
Reorganization items, net	(8,663)			(62,640)
Other, net	107		82	349	520
Loss before income tax (expense) benefit	(98,511)		(102,610)	(1,125,119)	(321,342)
Income tax benefit	(95)		7,482	19,753	38,898
Net loss	$ (98,606)		$ (95,128)	$ (1,105,366)	$ (282,444)
Weighted-average shares outstanding:
Shares of common stock	138,054		137,694	137,976	137,636
Total weighted-average shares outstanding	138,054		137,694	137,976	137,636
Contract Drilling [Member]
Revenues:
Total revenues	$ 129,345		$ 242,315	$ 535,848	$ 676,284
Operating expenses:
Contract drilling, excluding depreciation	130,921		201,568	481,376	593,779
Reimbursable Expenses [Member]
Revenues:
Total revenues	8,912		11,705	29,782	27,984
Operating expenses:
Contract drilling, excluding depreciation	$ 8,578		$ 11,423	27,997	$ 27,479
Debtor [Member]
Revenues:
Total revenues				490,683
Operating expenses:
Depreciation				242,480
General and administrative				41,497
Impairment of assets				774,028
Restructuring and separation costs				15,383
Gain on disposition of assets				(3,989)
Total operating expenses				1,513,032
Operating loss				(1,022,349)
Other income (expense):
Interest income				502
Interest expense, net of amounts capitalized				(50,155)
Foreign currency transaction gain				591
Reorganization items, net				(62,640)
Other, net				(499)
Loss before income tax (expense) benefit				(1,134,550)
Income tax benefit				27,117
Net loss				(1,107,433)
Debtor [Member] | Contract Drilling [Member]
Revenues:
Total revenues				460,877
Operating expenses:
Contract drilling, excluding depreciation				415,613
Debtor [Member] | Reimbursable Expenses [Member]
Revenues:
Total revenues				29,806
Operating expenses:
Contract drilling, excluding depreciation				$ 28,020