Shareholders' Equity - Accumulated Other Comprehensive Income (Loss) (Details) $ in Millions	3 Months Ended
	Mar. 31, 2021 USD ($)
Summary of the components of accumulated other comprehensive income, net of tax
Balance at beginning of period	$ 974.3
Balance at end of period	981.7
Accumulated Other Comprehensive Income (Loss)
Summary of the components of accumulated other comprehensive income, net of tax
Balance at beginning of period	3.7
Other comprehensive income (loss) before reclassifications	(16.5)
Realized loss on amounts reclassified from other comprehensive income (loss), net of tax	0.7
Net current period other comprehensive income (loss)	(15.8)
Balance at end of period	(12.1)
Foreign Currency Translation
Summary of the components of accumulated other comprehensive income, net of tax
Balance at beginning of period	49.4
Other comprehensive income (loss) before reclassifications	(19.1)
Net current period other comprehensive income (loss)	(19.1)
Balance at end of period	30.3
Pension Liability Adjustment
Summary of the components of accumulated other comprehensive income, net of tax
Balance at beginning of period	(45.7)
Other comprehensive income (loss) before reclassifications	2.6
Realized loss on amounts reclassified from other comprehensive income (loss), net of tax	0.7
Net current period other comprehensive income (loss)	3.3
Balance at end of period	$ (42.4)