Segments and Geographic Area Analysis - Summary of Information about Disaggregated Revenue by Country (Detail) - USD ($) $ in Thousands	3 Months Ended		4 Months Ended	5 Months Ended	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Apr. 23, 2021	Sep. 30, 2021	Sep. 30, 2020
Segment Reporting Information [Line Items]
Total revenues	$ 213,877	$ 138,257	$ 169,379	$ 328,788	$ 565,630
Contract Drilling [Member]
Segment Reporting Information [Line Items]
Total revenues	183,156	129,345	153,364	281,189	535,848
Reimbursable Expenses [Member]
Segment Reporting Information [Line Items]
Total revenues	30,721	8,912	16,015	47,599	29,782
United States [Member]
Segment Reporting Information [Line Items]
Total revenues	89,029	60,092	100,263	148,538	253,576
United States [Member] | Contract Drilling [Member]
Segment Reporting Information [Line Items]
Total revenues	71,954	57,523	93,215	122,732	244,578
United States [Member] | Reimbursable Expenses [Member]
Segment Reporting Information [Line Items]
Total revenues	17,075	2,569	7,048	25,806	8,998
United Kingdom [Member]
Segment Reporting Information [Line Items]
Total revenues	23,847	27,376	30,267	37,715	94,024
United Kingdom [Member] | Contract Drilling [Member]
Segment Reporting Information [Line Items]
Total revenues	22,271	25,178	27,967	35,186	86,949
United Kingdom [Member] | Reimbursable Expenses [Member]
Segment Reporting Information [Line Items]
Total revenues	1,576	2,198	2,300	2,529	7,075
Australia [Member]
Segment Reporting Information [Line Items]
Total revenues	38,201	18,849	21,728	67,430	60,345
Australia [Member] | Contract Drilling [Member]
Segment Reporting Information [Line Items]
Total revenues	34,671	16,279	17,031	58,620	49,663
Australia [Member] | Reimbursable Expenses [Member]
Segment Reporting Information [Line Items]
Total revenues	3,530	2,570	4,697	8,810	10,682
Senegal [Member]
Segment Reporting Information [Line Items]
Total revenues	29,902			29,894
Senegal [Member] | Contract Drilling [Member]
Segment Reporting Information [Line Items]
Total revenues	23,223			23,223
Senegal [Member] | Reimbursable Expenses [Member]
Segment Reporting Information [Line Items]
Total revenues	6,679			6,671
Brazil [Member]
Segment Reporting Information [Line Items]
Total revenues	20,511	25,790	3,421	23,735	145,897
Brazil [Member] | Contract Drilling [Member]
Segment Reporting Information [Line Items]
Total revenues	20,511	25,774	3,421	23,735	145,921
Brazil [Member] | Reimbursable Expenses [Member]
Segment Reporting Information [Line Items]
Total revenues		16			(24)
Myanmar [Member]
Segment Reporting Information [Line Items]
Total revenues	12,387		13,700	21,476
Myanmar [Member] | Contract Drilling [Member]
Segment Reporting Information [Line Items]
Total revenues	10,526		11,730	17,693
Myanmar [Member] | Reimbursable Expenses [Member]
Segment Reporting Information [Line Items]
Total revenues	$ 1,861		$ 1,970	$ 3,783
Malaysia [Member]
Segment Reporting Information [Line Items]
Total revenues		6,150			11,788
Malaysia [Member] | Contract Drilling [Member]
Segment Reporting Information [Line Items]
Total revenues		4,591			8,737
Malaysia [Member] | Reimbursable Expenses [Member]
Segment Reporting Information [Line Items]
Total revenues		$ 1,559			$ 3,051