Assets Impairments - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2019 USD ($) Rig	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($) Rig
Schedule Of Asset Impairment Charges [Line Items]
Loss on impairment of assets | $		$ 27,225,000	$ 99,313,000
2019 Impaired Rigs [Member]
Schedule Of Asset Impairment Charges [Line Items]
Number of rigs evaluated for impairment | Rig	3
Loss on impairment of assets | $	$ 0
2018 Impaired Rigs [Member]
Schedule Of Asset Impairment Charges [Line Items]
Loss on impairment of assets | $		$ 27,200,000
Impaired long-lived assets held and used, method for determining fair value		We estimated the fair value of the impaired rig using a market approach based on a signed agreement to sell the rig, less estimated costs to sell. We considered this valuation approach to be a Level 3 fair value measurement due to the level of estimation involved as the sale had not yet been completed at the time of our analysis.
2017 Impaired Rigs [Member]
Schedule Of Asset Impairment Charges [Line Items]
Number of rigs evaluated for impairment | Rig			10
Loss on impairment of assets | $			$ 99,300,000
Number of rigs impaired | Rig			3
Number of rigs impaired based on income approach | Rig			2