Accumulated Other Comprehensive Income (Loss) and Equity (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Increase (Decrease) in Stockholders' Equity
Beginning Balance	$ 1,232.4	$ 889.0
Ending Balance	1,579.3	1,232.4
Accumulated other comprehensive income (loss)
Increase (Decrease) in Stockholders' Equity
Beginning Balance	(35.9)	(29.9)
Other comprehensive income (loss)	37.1	(6.4)
Amounts reclassified from accumulated other comprehensive income (loss), net of income taxes	1.2	0.4
Net current-period other comprehensive income (loss), net of taxes	38.3	(6.0)
Ending Balance	2.4	(35.9)
Foreign currency translation adjustments
Increase (Decrease) in Stockholders' Equity
Beginning Balance	(25.0)	(17.5)
Other comprehensive income (loss)	38.8	(7.5)
Amounts reclassified from accumulated other comprehensive income (loss), net of income taxes	0.0	0.0
Net current-period other comprehensive income (loss), net of taxes	38.8	(7.5)
Ending Balance	13.8	(25.0)
Pension liability adjustments, net of taxes
Increase (Decrease) in Stockholders' Equity
Beginning Balance	(10.9)	(12.4)
Other comprehensive income (loss)	(1.7)	1.1
Amounts reclassified from accumulated other comprehensive income (loss), net of income taxes	1.2	0.4
Net current-period other comprehensive income (loss), net of taxes	(0.5)	1.5
Ending Balance	$ (11.4)	$ (10.9)