Income Taxes - Additional Details (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Loss Carryforwards [Line Items]
Amount of deferred tax liability derecognized			$ 255.7
Provisional net tax benefit			(156.5)
Discrete tax benefit due to amended returns	$ (1.0)	$ (0.4)	3.2
Deferred income tax liabilities	30.5	28.5
Valuation allowance on deferred tax assets	31.8	26.1	$ 31.2	$ 45.5
Tax Credit carryforwards	0.7
Unrecognized tax benefits that would affect the annual effective rate if recognized	2.0
Accrual for the payment of interest and penalties	0.1	0.1
Deferred Tax Assets, Foreign Subsidiaries
Operating Loss Carryforwards [Line Items]
Reduction in valuation allowance related to international subsidiary		$ 2.0
International
Operating Loss Carryforwards [Line Items]
Valuation allowance on deferred tax assets	31.8
Operating loss carryforwards	110.0
International | Australian Taxation Office
Operating Loss Carryforwards [Line Items]
Reduction in valuation allowance related to international subsidiary	$ (4.8)