Debt - Interest Rates (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
New Ultraco Debt Facility
Debt Instrument [Line Items]
Commitment fee percentage	40.00%	40.00%	40.00%	40.00%
Norwegian Bond Debt Facility
Debt Instrument [Line Items]
Interest rate		8.25%		8.25%
Norwegian Bond Debt Facility | Senior Subordinated Notes
Debt Instrument [Line Items]
Interest rate	8.25%		8.25%
Super Senior Facility
Debt Instrument [Line Items]
Commitment fee percentage		40.00%		40.00%
Super Senior Facility | Senior Subordinated Notes
Debt Instrument [Line Items]
Interest rate		2.79%	2.58%	3.19%
Holdco Revolving Facility
Debt Instrument [Line Items]
Commitment fee percentage	40.00%		40.00%
Holdco Revolving Facility | Senior Subordinated Notes
Debt Instrument [Line Items]
Interest rate	2.55%
Minimum | Convertible Bond Debt
Debt Instrument [Line Items]
Interest rate	5.00%	500.00%	5.00%	500.00%
Minimum | New Ultraco Debt Facility
Debt Instrument [Line Items]
Interest rate	2.61%	2.73%	2.60%	2.73%
Minimum | Super Senior Facility | Senior Subordinated Notes
Debt Instrument [Line Items]
Interest rate		2.43%	2.24%	2.89%
Minimum | Holdco Revolving Facility | Senior Subordinated Notes
Debt Instrument [Line Items]
Interest rate			2.55%
Weighted Average | Convertible Bond Debt
Debt Instrument [Line Items]
Interest rate	10.14%	10.14%	10.14%	10.14%
Weighted Average | New Ultraco Debt Facility
Debt Instrument [Line Items]
Interest rate		3.56%		4.23%
Weighted Average | New Ultraco Debt Facility | Senior Subordinated Notes
Debt Instrument [Line Items]
Interest rate	3.39%		3.28%
Weighted Average | Norwegian Bond Debt Facility
Debt Instrument [Line Items]
Interest rate		9.01%		8.96%
Weighted Average | Norwegian Bond Debt Facility | Senior Subordinated Notes
Debt Instrument [Line Items]
Interest rate	9.05%		9.02%
Weighted Average | Holdco Revolving Facility | Senior Subordinated Notes
Debt Instrument [Line Items]
Interest rate	6.15%		5.61%
Maximum | New Ultraco Debt Facility
Debt Instrument [Line Items]
Interest rate	2.68%	4.28%	2.72%	4.68%
Maximum | Holdco Revolving Facility | Senior Subordinated Notes
Debt Instrument [Line Items]
Interest rate			2.60%