CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (Unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (50.1)	$ 13.6	$ (33.7)	$ 25.4
Reclassification of amounts recognized in the condensed consolidated statements of operations:
Amortization of adjustments to pension and other postretirement benefit liabilities (Note 6)	1.5	1.4	3.1	3.1
Unrealized foreign currency translation gain (loss)	3.6	1.5	(0.4)	(1.7)
Net gain from pension and other postretirement benefit plans	0.0	4.9	0.0	4.9
Income from other comprehensive income items	5.1	7.8	2.7	6.3
Provision for income taxes	0.4	1.6	0.6	1.8
Other comprehensive income	4.7	6.2	2.1	4.5
Comprehensive income (loss)	$ (45.4)	$ 19.8	$ (31.6)	$ 29.9