Debt - Additional Information (Details) - USD ($)				1 Months Ended			8 Months Ended	9 Months Ended
	Feb. 05, 2021	Jul. 20, 2020	Apr. 20, 2020	Feb. 05, 2021	Feb. 28, 2019	Sep. 30, 2018	Sep. 30, 2021	Sep. 30, 2020	Feb. 04, 2021	Apr. 30, 2020	Jul. 31, 2019	Dec. 21, 2017
Debt Instrument [Line Items]
Repayments of debt				$ 0			$ 0	$ 101,132,000
Rig, Noble Joe Knight
Debt Instrument [Line Items]
Purchase price of asset acquired					$ 83,800,000
Rig, Noble Johnny Whitstine
Debt Instrument [Line Items]
Purchase price of asset acquired						$ 93,800,000
Interest Payable In Cash | Second Lien Notes Indenture
Debt Instrument [Line Items]
Debtor-in-possession financing, Interest rate on borrowings	11.00%			11.00%
Interest Payable Half In Cash And Half By Issuing P I K Notes | Second Lien Notes Indenture
Debt Instrument [Line Items]
Debtor-in-possession financing, Interest rate on borrowings	13.00%			13.00%
Interest Payable By Issuing P I K Notes | Second Lien Notes Indenture
Debt Instrument [Line Items]
Debtor-in-possession financing, Interest rate on borrowings	15.00%			15.00%
Participants In The Rights Offering | Ordinary Shares
Debt Instrument [Line Items]
Plan of reorganization, shares issued, subscription price	$ 200,000,000			$ 200,000,000
Participants In The Rights Offering | Ordinary Shares | Second Lien Notes Indenture
Debt Instrument [Line Items]
Plan of reorganization, shares issued, subscription price	200,000,000			200,000,000
Line of Credit | The 2017 Credit Facility
Debt Instrument [Line Items]
Maximum borrowing capacity under credit facilities											$ 1,300,000,000	$ 1,500,000,000
Borrowings outstanding or letters of credit issued									$ 545,000,000.0
Secured notes | Second Lien Notes Indenture
Debt Instrument [Line Items]
Debtor-in-possession financing, amount arranged	216,000,000			216,000,000
Debtor-in-possession financing, backstop fee	$ 16,000,000
Debt redemption rice, percentage of principal amount redeemed	106.00%
Debt redemption, change of control period	120 days
Secured notes | 2019 Seller Loan
Debt Instrument [Line Items]
Financed value					$ 53,600,000
Repayments of debt			$ 48,100,000
Secured notes | 2018 Seller Loan
Debt Instrument [Line Items]
Financed value						$ 60,000,000
Repayments of debt			$ 53,600,000
Period following payment date for debt termination		90 days
Long-term debt		$ 0
Secured notes | Seller loans
Debt Instrument [Line Items]
Principal payment due at the end of the term, percentage										85.00%
Credit facility | Line of Credit | Exit Credit Agreement
Debt Instrument [Line Items]
Debtor-in-possession financing, amount arranged	$ 675,000,000			675,000,000
Debtor-in-possession financing, borrowings outstanding	$ 177,500,000			$ 177,500,000			190,000,000
Debtor-in-possession financing, increase of basis spread on variable rate	5000.00%			5000.00%
Debtor-in-possession financing, basis spread on variable rate, additional increase under conditions	5000.00%			5000.00%
Debt restrictive covenants, maximum available cash after borrowings	$ 100,000,000			$ 100,000,000
Debt covenant, consolidated leverage ratio (maximum)	5.50			5.50
Debt restrictive covenants, outstanding borrowing	$ 610,000,000			$ 610,000,000
Debt restrictive covenants, asset coverage ratio	2.00			2.00
Debt mandatory prepayments term, available cash benchmark	$ 150,000,000			$ 150,000,000
Minimum liquidity	$ 25,000,000			$ 25,000,000
Debt financial maintenance covenant, ratio of asset coverage aggregate rig value to aggregate principal amount of loans and letters of credit outstanding	2.00			2.00
Credit facility | Line of Credit | Debt Covenant Period One | Exit Credit Agreement
Debt Instrument [Line Items]
Debt financial maintenance covenant, ratio of adjusted EBITDA to cash interest expense	2.00			2.00
Credit facility | Line of Credit | Debt Covenant Period Two | Exit Credit Agreement
Debt Instrument [Line Items]
Debt financial maintenance covenant, ratio of adjusted EBITDA to cash interest expense	2.25			2.25
Credit facility | Line of Credit | LIBOR | Exit Credit Agreement
Debt Instrument [Line Items]
Debtor-in-possession financing, increase of basis spread on variable rate	4.75%			4.75%
Credit facility | Line of Credit | Base Rate | Exit Credit Agreement
Debt Instrument [Line Items]
Debtor-in-possession financing, basis spread on variable rate	3.75%			3.75%
Credit facility | Line of Credit | Base Rate | Exit Credit Agreement | Reserve-Adjusted One-Month LIBOR
Debt Instrument [Line Items]
Debtor-in-possession financing, increase of basis spread on variable rate	1.00%			1.00%
Credit facility | Line of Credit | Fed Funds Effective Rate | Exit Credit Agreement
Debt Instrument [Line Items]
Debtor-in-possession financing, increase of basis spread on variable rate	0.50%			0.50%
Credit facility | Letters of credit
Debt Instrument [Line Items]
Debtor-in-possession financing, letters of credit outstanding							8,700,000
Credit facility | Letters of credit | Exit Credit Agreement
Debt Instrument [Line Items]
Debtor-in-possession financing, letters of credit outstanding	$ 8,800,000			$ 8,800,000
Credit facility | Unsecured Debt
Debt Instrument [Line Items]
Debtor-in-possession financing, letters of credit outstanding							$ 11,700,000
Letters of credit | Line of Credit | Exit Credit Agreement
Debt Instrument [Line Items]
Debtor-in-possession financing, amount arranged	$ 67,500,000			$ 67,500,000