Other (Expense) Income, net (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Other Income and Expenses [Abstract]
Interest and dividend income	$ 4.9	$ 1.7	$ 10.3	$ 5.3
Net foreign exchange transaction (losses) gains	(0.3)	0.9	(7.8)	5.7
Bank fee expense	(1.4)	(1.2)	(4.6)	(3.9)
Net (loss) gain on disposals of business and property and equipment	(0.9)	0.2	1.3	(2.9)
Other, net	(2.3)	(1.2)	(5.4)	(2.8)
Other (expense) income, net	$ 0.0	$ 0.4	$ (6.2)	$ 1.4