Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 63.2	$ 57.7	$ 45.5
Other comprehensive income (loss), net of tax:
Defined benefit plan adjustments (Note 15)	(0.4)	(0.2)	(0.2)
Foreign currency translation gain (loss), net (Note 15)	1.9	2.9	(5.5)
Other comprehensive income (loss), net of tax	1.5	2.7	(5.7)
Comprehensive income	$ 64.7	$ 60.4	$ 39.8