CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 80.3	$ 73.0	$ 51.1
Reclassification of amounts recognized in the consolidated statement of operations:
Amortization of adjustments to pension and other postretirement benefit liabilities	5.9	7.2	7.1
Pension plan settlement/curtailment charge (2015 amount in discontinued operations)	0.6	0.8	5.5
Amounts recognized in the consolidated statement of operations	6.5	8.0	12.6
Unrealized foreign currency translation gain (loss)	20.0	(7.1)	(15.0)
Net loss from pension and other postretirement benefit plans	(20.3)	(18.0)	(6.3)
Deferred loss on available-for-sale securities	(0.4)	0.0	0.0
Income (loss) from other comprehensive income items before income taxes	5.8	(17.1)	(8.7)
(Benefit) provision for income taxes	(3.0)	(3.4)	1.2
Other comprehensive income (loss)	8.8	(13.7)	(9.9)
Comprehensive income	$ 89.1	$ 59.3	$ 41.2