Goodwill and Other Intangible Assets - Fair Value of Goodwill and Intangible Assets (Details) - USD ($) $ in Millions	Dec. 31, 2020	Apr. 07, 2020	Jun. 28, 2019	Apr. 04, 2019	Apr. 01, 2019
NSM
Finite-Lived Intangible Assets [Line Items]
Goodwill and intangible assets acquired	$ 281.8
Renewal rights
Finite-Lived Intangible Assets [Line Items]
Goodwill and intangible assets acquired			$ 82.5
Embrace
Finite-Lived Intangible Assets [Line Items]
Goodwill and intangible assets acquired					$ 67.6
Kingsbridge
Finite-Lived Intangible Assets [Line Items]
Goodwill and intangible assets acquired		$ 131.7
Kudu Transaction
Finite-Lived Intangible Assets [Line Items]
Goodwill and intangible assets acquired				$ 9.8
Other Operations
Finite-Lived Intangible Assets [Line Items]
Goodwill and intangible assets acquired	$ 38.1
Other Assets | Embrace
Finite-Lived Intangible Assets [Line Items]
Software					$ 3.4