Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2016	Mar. 31, 2015
Statement of Comprehensive Income [Abstract]
Net income	$ 32.6	$ 21.4	$ 89.6	$ 61.5
Unrealized gain (loss) on available-for-sale securities, net of tax	0.3		0.2	(0.3)
Change in foreign currency translation adjustment, net of tax	0.5	(3.3)	(1.5)	(5.7)
Comprehensive income	$ 33.4	$ 18.1	$ 88.3	$ 55.5