Segments and Geographic Area Analysis - Summary of Information about Disaggregated Revenue by Country (Detail) - USD ($) $ in Thousands	1 Months Ended	2 Months Ended	3 Months Ended	4 Months Ended	6 Months Ended
	Apr. 23, 2021	Jun. 30, 2021	Jun. 30, 2020	Apr. 23, 2021	Jun. 30, 2020
Segment Reporting Information [Line Items]
Total revenues	$ 34,562	$ 114,911	$ 198,203	$ 169,379	$ 427,373
Contract Drilling [Member]
Segment Reporting Information [Line Items]
Total revenues	30,811	98,033	188,637	153,364	406,503
Reimbursable Expenses [Member]
Segment Reporting Information [Line Items]
Total revenues	3,751	16,878	9,566	16,015	20,870
United States [Member]
Segment Reporting Information [Line Items]
Total revenues	20,226	59,500	85,438	100,263	193,481
United States [Member] | Contract Drilling [Member]
Segment Reporting Information [Line Items]
Total revenues	19,171	50,777	82,154	93,215	187,054
United States [Member] | Reimbursable Expenses [Member]
Segment Reporting Information [Line Items]
Total revenues	1,055	8,723	3,284	7,048	6,427
United Kingdom [Member]
Segment Reporting Information [Line Items]
Total revenues	4,226	13,868	30,806	30,267	66,650
United Kingdom [Member] | Contract Drilling [Member]
Segment Reporting Information [Line Items]
Total revenues	3,876	12,915	29,173	27,967	61,772
United Kingdom [Member] | Reimbursable Expenses [Member]
Segment Reporting Information [Line Items]
Total revenues	350	953	1,633	2,300	4,878
Australia [Member]
Segment Reporting Information [Line Items]
Total revenues	6,900	29,229	19,478	21,728	41,495
Australia [Member] | Contract Drilling [Member]
Segment Reporting Information [Line Items]
Total revenues	5,357	23,949	16,195	17,031	33,383
Australia [Member] | Reimbursable Expenses [Member]
Segment Reporting Information [Line Items]
Total revenues	1,543	5,280	3,283	4,697	8,112
Myanmar [Member]
Segment Reporting Information [Line Items]
Total revenues	3,210	9,090		13,700
Myanmar [Member] | Contract Drilling [Member]
Segment Reporting Information [Line Items]
Total revenues	2,407	7,168		11,730
Myanmar [Member] | Reimbursable Expenses [Member]
Segment Reporting Information [Line Items]
Total revenues	$ 803	1,922		1,970
Brazil [Member]
Segment Reporting Information [Line Items]
Total revenues		3,224	56,982	3,421	120,108
Brazil [Member] | Contract Drilling [Member]
Segment Reporting Information [Line Items]
Total revenues		$ 3,224	56,968	$ 3,421	120,147
Brazil [Member] | Reimbursable Expenses [Member]
Segment Reporting Information [Line Items]
Total revenues			14		(39)
Malaysia [Member]
Segment Reporting Information [Line Items]
Total revenues			5,499		5,639
Malaysia [Member] | Contract Drilling [Member]
Segment Reporting Information [Line Items]
Total revenues			4,147		4,147
Malaysia [Member] | Reimbursable Expenses [Member]
Segment Reporting Information [Line Items]
Total revenues			$ 1,352		$ 1,492