CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 16.2	$ 17.6
Unrealized foreign currency translation gain	5.5	1.7
Reclassification of amortization of adjustments to pension and other postretirement benefit liabilities recognized in net periodic benefit cost (Note 8)	1.6	2.0
Reclassification of pension settlement charge (Note 8)	0.8	0.0
Net gain from pension and other postretirement benefit plans (Note 5)	0.4	0.0
Unrealized gain on available-for-sale securities	0.0	0.1
Income from other comprehensive income items	8.3	3.8
Provision for income taxes	1.0	0.8
Other comprehensive income	7.3	3.0
Comprehensive income	$ 23.5	$ 20.6