Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Apr. 06, 2020	Dec. 31, 2019
Income Tax Contingency [Line Items]
Income before income taxes	$ (32.5)	$ 29.6	$ (75.0)	$ 197.3
Benefit from (provision for) income taxes	12.8	$ (10.2)	10.3	$ (35.1)
KWE [Member]
Income Tax Contingency [Line Items]
Foreign partnership investment basis difference	84.0		84.0			$ 77.1
Valuation allowance	$ 75.2		$ 75.2			$ 72.6
Interest Expense Carryover Uncertainty [Member] | KWE [Member]
Income Tax Contingency [Line Items]
Valuation allowance					$ 3.9