CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income before allocation to noncontrolling interests	$ 172.5	$ 123.8	$ 230.0
Other comprehensive income (loss), net of tax
Currency translation adjustment	86.9	(64.7)	(70.1)
Changes in pension and postretirement plan assets and benefit obligation, net of tax	9.2	(35.2)	(8.4)
Net current-period other comprehensive income	96.1	(99.9)	(78.5)
Comprehensive income (loss) before allocation to noncontrolling interests	268.6	23.9	151.5
Less: Noncontrolling interests in comprehensive income (loss)	(0.7)	(1.0)	(1.1)
Net Income (Loss) Attributable to Noncontrolling Interest	0.7	1.0	1.1
Comprehensive income (loss) attributable to common shareholders	$ 267.9	$ 22.9	$ 150.4