Consolidated Statements of Comprehensive Income - 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	$ 14.4	$ 1.4	$ 12.3	$ 5.8
Other comprehensive income (loss), net of tax:
Currency translation adjustment	0.6	(0.4)	(2.8)	(1.2)
Unrealized (loss) gain on available-for-sale debt securities	(0.4)	0.7	0.4	1.3
Total other comprehensive income (loss), net of tax	0.2	0.3	(2.4)	0.1
Comprehensive income	$ 14.6	$ 1.7	$ 9.9	$ 5.9