Revenues - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021		Jun. 30, 2020	Dec. 31, 2020
Disaggregation Of Revenue [Line Items]
Accounts receivable balances	$ 196,654,000		$ 196,654,000			$ 160,214,000
Revenue	291,774,000	$ 250,380,000	532,703,000		$ 696,307,000
ASC Topic 606 Revenue from Contracts with Customers
Disaggregation Of Revenue [Line Items]
Accounts receivable balances	194,000,000		194,000,000			158,000,000
Revenue			2,300,000		0
ASC Topic 606 Revenue from Contracts with Customers | Accounts Payable
Disaggregation Of Revenue [Line Items]
Total contract liability	$ 500,000		500,000			$ 600,000
ASC Topic 606 Revenue from Contracts with Customers | Contract Drilling
Disaggregation Of Revenue [Line Items]
Amortized revenue			$ 0	[1]	$ 100,000
Maximum
Disaggregation Of Revenue [Line Items]
Accounts receivable payment terms			60 days
Minimum
Disaggregation Of Revenue [Line Items]
Accounts receivable payment terms			30 days

[1] no