CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Millions	Common Stock	Additional paid-in Capital	Accumulated Other Comprehensive Income/(Loss)	Accumulated Deficit	Total
Balance at Jun. 30, 2016	$ 0.2	$ 1,777.6	$ 4.5	$ (554.3)	$ 1,228.0
Balance, shares at Jun. 30, 2016	242,649,498
Stock-based compensation		104.7			104.7
Stock-based compensation, shares	3,822,053
Cumulative effect adjustment resulting from adoption of ASU 2016-09		1.7		(1.7)
Foreign currency translation adjustments			2.1		2.1
Defined benefit pension plan adjustments			(1.2)		(1.2)
Net income				87.1	87.1
Balance at Jun. 30, 2017	$ 0.2	1,884.0	5.4	(468.9)	1,420.7
Balance, shares at Jun. 30, 2017	246,471,551
Stock-based compensation		91.1			91.1
Stock-based compensation, shares	2,716,011
Foreign currency translation adjustments			(7.4)		(7.4)
Repurchase and retirement of common shares		(93.5)			(93.5)
Repurchase and retirement of common shares (in shares)	(2,749,079)
Defined benefit pension plan adjustments			(13.5)		(13.5)
Net income				102.9	102.9
Balance at Jun. 30, 2018	$ 0.2	1,881.6	(15.5)	(366.0)	$ 1,500.3
Balance, shares at Jun. 30, 2018	246,438,483				246,438,483
Stock-based compensation		102.1			$ 102.1
Stock-based compensation, shares	2,793,302
Foreign currency translation adjustments			(7.2)		(7.2)
Repurchase and retirement of common shares		(402.5)			(402.5)
Repurchase and retirement of common shares (in shares)	(12,973,892)
Defined benefit pension plan adjustments			(1.2)		(1.2)
Net income				150.0	150.0
Balance at Jun. 30, 2019	$ 0.2	$ 1,581.2	$ (23.9)	$ (216.0)	$ 1,341.5
Balance, shares at Jun. 30, 2019	236,257,893				236,257,893