Other Comprehensive Income (Loss) - Components of OCI (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss)	$ 1.5	$ 2.7	$ (5.7)
Net actuarial (loss) gain during the year
Accumulated Other Comprehensive Income (Loss) [Line Items]
Defined benefit plan adjustments, before tax	(0.5)	(0.3)	(0.4)
Defined benefit plan adjustments, tax effect	0.1	0.1	0.1
Defined benefit plan adjustments, net of tax	(0.4)	(0.2)	(0.3)
Amortization of net actuarial gain (loss) included in net income, before tax	0.0	0.0	0.1
Amortization of net actuarial gain (loss) included in net income, tax effect	0.0	0.0	0.0
Amortization of net actuarial gain (loss) included in net income, net of tax	0.0	0.0	0.1
Other comprehensive income (loss), before tax	(0.5)	(0.3)	(0.3)
Other comprehensive income (loss), tax effect	0.1	0.1	0.1
Other comprehensive income (loss)	(0.4)	(0.2)	(0.2)
Foreign currency translation gain (loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before tax	0.8	2.9	(5.5)
Other comprehensive income (loss), tax effect	1.1	0.0	0.0
Other comprehensive income (loss)	1.9	2.9	(5.5)
Other comprehensive income (loss)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive income (loss), before tax	0.3	2.6	(5.8)
Other comprehensive income (loss), tax effect	1.2	0.1	0.1
Other comprehensive income (loss)	$ 1.5	$ 2.7	$ (5.7)