Impairment of Assets - Additional Information (Detail) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2021 USD ($) Rig	Mar. 31, 2020 USD ($) Rig	Dec. 31, 2020 Rig
Schedule Of Asset Impairment Charges [Line Items]
Number of rigs impaired during period	1		1
Impairment of assets | $	$ 197,027	$ 774,028
2021 Impaired Rigs [Member]
Schedule Of Asset Impairment Charges [Line Items]
Number of rigs evaluated for impairment	3
Number of rigs impaired during period	1
Impairment of assets | $	$ 197,000
2020 Impaired Rigs [Member]
Schedule Of Asset Impairment Charges [Line Items]
Number of rigs evaluated for impairment		5
Number of rigs impaired during period		4
Impairment of assets | $		$ 774,000