CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 16.4	$ 6.1	$ 56.6	$ 39.1
Unrealized foreign currency translation gain (loss)	0.7	1.8	0.9	(9.1)
Reclassification of amortization of adjustments to pension and other postretirement benefit liabilities recognized in net periodic benefit cost (Note 6)	1.9	1.8	5.5	5.4
Unrealized gain on “available-for-sale” securities	0.0	0.0	0.1	0.0
Income (loss) from other comprehensive income items	2.6	3.6	6.5	(3.7)
Provision for income taxes	0.7	0.7	2.1	2.0
Other comprehensive income (loss)	1.9	2.9	4.4	(5.7)
Comprehensive income	$ 18.3	$ 9.0	$ 61.0	$ 33.4