Discontinued Operations - Additional Information (Details) - MCC Business - Discontinued Operations, Held-for-sale - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Discontinued Operations
Overhead expenses previously allocated	$ 7.2	$ 8.0	$ 21.0	$ 25.6
Excess capital and undistributed earnings	165.0		165.0
Excess capital and undistributed earnings distributed	$ 37.5		$ 37.5

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