Income Taxes - Net Operating and Capital Loss Carryforwards (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Net deferred tax assets
Total net deferred tax assets	$ 70.4	$ 88.1
Tax credit carryforwards, foreign	5.5
Operating and Capital Loss Carryforward
Net deferred tax assets
Operating loss carryforwards	584.4
Gross deferred tax asset	128.0
Valuation allowance	(115.6)
Total net deferred tax assets	12.4
Operating and Capital Loss Carryforward | United States
Net deferred tax assets
Operating loss carryforwards	369.1
Gross deferred tax asset	77.5
Valuation allowance	(66.8)
Total net deferred tax assets	10.7
Operating and Capital Loss Carryforward | Luxembourg
Net deferred tax assets
Operating loss carryforwards	104.2
Gross deferred tax asset	26.0
Valuation allowance	(25.9)
Total net deferred tax assets	0.1
Operating and Capital Loss Carryforward | United Kingdom
Net deferred tax assets
Operating loss carryforwards	25.9
Gross deferred tax asset	4.9
Valuation allowance	(3.3)
Total net deferred tax assets	1.6
Operating and Capital Loss Carryforward | Israel
Net deferred tax assets
Operating loss carryforwards	85.2
Gross deferred tax asset	19.6
Valuation allowance	(19.6)
Total net deferred tax assets	0.0
2020-2024 | Operating and Capital Loss Carryforward
Net deferred tax assets
Operating loss carryforwards	0.0
2020-2024 | Operating and Capital Loss Carryforward | United States
Net deferred tax assets
Operating loss carryforwards	0.0
2020-2024 | Operating and Capital Loss Carryforward | Luxembourg
Net deferred tax assets
Operating loss carryforwards	0.0
2020-2024 | Operating and Capital Loss Carryforward | United Kingdom
Net deferred tax assets
Operating loss carryforwards	0.0
2020-2024 | Operating and Capital Loss Carryforward | Israel
Net deferred tax assets
Operating loss carryforwards	0.0
2025-2029 | Operating and Capital Loss Carryforward
Net deferred tax assets
Operating loss carryforwards	0.0
2025-2029 | Operating and Capital Loss Carryforward | United States
Net deferred tax assets
Operating loss carryforwards	0.0
2025-2029 | Operating and Capital Loss Carryforward | Luxembourg
Net deferred tax assets
Operating loss carryforwards	0.0
2025-2029 | Operating and Capital Loss Carryforward | United Kingdom
Net deferred tax assets
Operating loss carryforwards	0.0
2025-2029 | Operating and Capital Loss Carryforward | Israel
Net deferred tax assets
Operating loss carryforwards	0.0
2030-2039 | Operating and Capital Loss Carryforward
Net deferred tax assets
Operating loss carryforwards	323.9
2030-2039 | Operating and Capital Loss Carryforward | United States
Net deferred tax assets
Operating loss carryforwards	250.7
2030-2039 | Operating and Capital Loss Carryforward | Luxembourg
Net deferred tax assets
Operating loss carryforwards	73.2
2030-2039 | Operating and Capital Loss Carryforward | United Kingdom
Net deferred tax assets
Operating loss carryforwards	0.0
2030-2039 | Operating and Capital Loss Carryforward | Israel
Net deferred tax assets
Operating loss carryforwards	0.0
No expiration date | Operating and Capital Loss Carryforward
Net deferred tax assets
Operating loss carryforwards	260.5
No expiration date | Operating and Capital Loss Carryforward | United States
Net deferred tax assets
Operating loss carryforwards	118.4
No expiration date | Operating and Capital Loss Carryforward | Luxembourg
Net deferred tax assets
Operating loss carryforwards	31.0
No expiration date | Operating and Capital Loss Carryforward | United Kingdom
Net deferred tax assets
Operating loss carryforwards	25.9
No expiration date | Operating and Capital Loss Carryforward | Israel
Net deferred tax assets
Operating loss carryforwards	$ 85.2