Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 10.3	$ 3.8
Defined benefit pension and other postretirement employee benefits:
Amortization of actuarial loss included in net periodic cost, net of tax of $0.6 and $0.5	1.8	1.2
Other comprehensive income (loss), net of tax	1.8	1.2
Comprehensive income	$ 12.1	$ 5.0