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Significant Transactions - Ark (Details) - USD ($) $ in Millions			3 Months Ended
	Jan. 01, 2021	Oct. 01, 2020	Mar. 31, 2021	Dec. 31, 2020
Other Significant Noncash Transactions [Line Items]
Goodwill and other intangible assets			$ 1,037.0	$ 782.4
Ark
Other Significant Noncash Transactions [Line Items]
Cash pre-funded/placed in escrow for Ark Transaction				366.3
Other Operations
Other Significant Noncash Transactions [Line Items]
Goodwill and other intangible assets			35.7	36.4
Cash pre-funded/placed in escrow for Ark Transaction			0.0	646.3
Ark
Other Significant Noncash Transactions [Line Items]
Goodwill and other intangible assets			292.5	0.0
Contingent consideration related to the Ark Transaction			$ 22.5	0.0
Ownership interest (as a percent)			72.00%
Ark \| Ark
Other Significant Noncash Transactions [Line Items]
Fully diluted ownership interest (as a percent)	63.00%
Ark \| Lloyd
Other Significant Noncash Transactions [Line Items]
Cash pre-funded/placed in escrow for Ark Transaction				$ 280.0
Ark
Other Significant Noncash Transactions [Line Items]
Merger agreement, equity capital contributed		$ 605.4
Equity capital, pre money valuation amount		300.0
Additional equity purchase from shareholders		$ 40.9
Assets acquired	$ 2,500.0
Goodwill and other intangible assets	292.5
Liabilities acquired	1,700.0
Contingent consideration related to the Ark Transaction	22.5
Noncontrolling interest acquired	220.2
Investment, potential additional contribution of equity capital	$ 200.0		$ 200.0
Ownership interest after additional funding			77.10%
Fully diluted ownership interest after additional funding			67.50%
Percent of shares outstanding			12.50%
Transaction costs			$ 25.3
Ark \| Ark
Other Significant Noncash Transactions [Line Items]
Percent of outstanding shares after performance obligations are satisfied	12.50%
Ownership interest (as a percent)			72.00%
Fully diluted ownership interest (as a percent)			63.00%
Investment, potential additional contribution of equity capital	$ 200.0
Ownership interest after additional funding	77.10%
Fully diluted ownership interest after additional funding	67.50%