CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 206.9	$ 150.7	$ 143.6
Other comprehensive (loss) income, net of tax:
Foreign currency translation adjustments	(39.2)	68.8	(18.1)
Prior service (cost) credit arising during period, net of tax of $0 and $1.1	(0.3)	0.0	1.9
Net actuarial (loss) gain arising during period, net of tax of $(0.2), $1.3 and $(4.8)	(0.7)	6.3	(11.1)
Settlement effects arising during period, net of tax of $1.1	0.0	0.0	2.0
Less: amortization of actuarial loss, net of tax of $0.3, $0.5 and $1.2	1.1	3.6	2.2
Less: amortization of prior service credit, net of tax of $(0.5), $(0.5) and $(0.5)	(1.5)	(3.5)	(0.9)
Less: amortization of transition obligation	0.0	0.0	0.1
Net loss on investment securities, net of tax of $(0.1), $(2.5) and $(0.1)	(0.1)	(4.7)	(0.2)
Net gain (loss) on derivatives, net of tax of $1.5, $(0.1) and $0.1	3.8	(1.0)	(0.1)
Other comprehensive (loss) income, net of tax	(36.9)	69.5	(24.2)
Comprehensive income	$ 170.0	$ 220.2	$ 119.4