Amount before allocation of valuation allowances of deferred tax asset attributable to deductible foreign tax credit carryforwards.

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Income Taxes - Valuation allowance (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Valuation allowance
Valuation allowance	$ 28.7	$ 7.1
Provision for income taxes	70.0	43.6	$ 1.9
Foreign tax credit carryforwards	22.0
Foreign Tax Credits
Valuation allowance
Valuation allowance	22.0
U.S. \| Capital Losses
Valuation allowance
Valuation allowance	0.3	1.5
Austria \| Operating Losses
Valuation allowance
Valuation allowance	$ 6.4	$ 5.7