Supplemental Financial Information - Accrued Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2021	Apr. 23, 2021	Dec. 31, 2020
Payables And Accruals [Abstract]
Deferred revenue	$ 38,564		$ 51,763
Payroll and benefits	31,122		30,296
Rig operating costs	27,678		21,123
Current operating lease liability	16,354		5,072
Personal injury and other claims	5,710		6,495
Shorebase and administrative costs	5,536		17,275
Interest payable	5,254
Accrued capital project/upgrade costs	3,096		7,075
Other	872		1,689
Change in accrued liabilities	$ 134,186	$ 123,055	$ 140,788