Income Taxes - Schedule of Pre-Tax Income (Loss) and Effective Income Tax Rates (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Income Tax Examination [Line Items]
Pre-Tax Income (Loss)	$ (4.1)	$ 78.7	$ 7.9	$ 109.9
Effective Tax Rate	(295.10%)	11.30%	320.40%	9.30%
Bermuda
Income Tax Examination [Line Items]
Pre-Tax Income (Loss)	$ (49.1)	$ 2.3	$ (49.0)	$ 7.3
Effective Tax Rate	0.00%	0.00%	0.00%	0.00%
United States
Income Tax Examination [Line Items]
Pre-Tax Income (Loss)	$ 46.0	$ 64.0	$ 84.7	$ 105.2
Effective Tax Rate	21.40%	21.90%	21.70%	19.40%
United Kingdom
Income Tax Examination [Line Items]
Pre-Tax Income (Loss)	$ 8.7	$ 9.3	$ 13.7	$ (8.9)
Effective Tax Rate	26.80%	(54.60%)	46.60%	115.30%
Brazil
Income Tax Examination [Line Items]
Pre-Tax Income (Loss)	$ 0.0	$ 2.3	$ (0.1)	$ 4.0
Effective Tax Rate	0.00%	0.00%	(422.40%)	0.00%
United Arab Emirates
Income Tax Examination [Line Items]
Pre-Tax Income (Loss)	$ 0.2	$ 0.1	$ 0.8	$ 0.3
Effective Tax Rate	0.00%	0.00%	0.00%	0.00%
Ireland
Income Tax Examination [Line Items]
Pre-Tax Income (Loss)	$ (4.6)	$ 0.0	$ (38.0)	$ (0.1)
Effective Tax Rate	0.00%	0.00%	0.00%	0.00%
Italy
Income Tax Examination [Line Items]
Pre-Tax Income (Loss)	$ (0.2)	$ 0.4	$ (0.1)	$ 1.2
Effective Tax Rate	46.70%	0.00%	(28.90%)	0.00%
Malta
Income Tax Examination [Line Items]
Pre-Tax Income (Loss)	$ (5.1)	$ 0.3	$ (4.1)	$ 0.9
Effective Tax Rate	0.00%	0.00%	0.00%	0.00%