Drilling and Other Property and Equipment - Additional Information (Detail) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Apr. 30, 2019	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Property Plant And Equipment [Line Items]
Gain (loss) on disposition of assets		$ (6,340)	$ 506	$ (1,191)	$ 1,066
Semisubmersible Rig [Member]
Property Plant And Equipment [Line Items]
Gain (loss) on disposition of assets	$ 14,300
Other Property and Equipment [Member]
Property Plant And Equipment [Line Items]
Gain (loss) on disposition of assets				$ (15,500)