Income Taxes - Schedule of Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits (Detail) - USD ($) $ in Millions	12 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2013
Income Tax Reconciliation [Line Items]
Unrecognized tax benefits at the beginning of year	$ 24.2	$ 10.9	$ 10.2
Gross increases - current year tax positions	1.1	1.8	0.7
Gross increases - prior year tax positions	1.0	0.3
Gross increases - acquisitions		14.2
Gross decreases - prior year tax positions		(3.0)
Unrecognized tax benefits at end of year	26.3	24.2	10.9
Interest and penalties in year-end balance	$ 1.0	$ 0.6	$ 0.3