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Income Taxes - Schedule of Reconciliation of Beginning and Ending Unrecognized Tax Benefits (Detail) - USD ($) $ in Millions	12 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2017
Income Tax Disclosure [Abstract]
Unrecognized tax benefits at the beginning of year	$ 24.9	$ 25.2	$ 24.2
Gross increases - current year tax positions	2.2	0.6	0.7
Gross increases - prior year tax positions	0.5	2.4	0.7
Gross increases - acquisitions	2.3
Gross decreases - prior year tax positions	(0.1)	(3.3)
Gross decreases - settlements	(2.7)
Gross decreases - statute lapse	(5.4)		(0.4)
Unrecognized tax benefits at end of year	21.7	24.9	25.2
Interest and penalties in year-end balance	$ 0.8	$ 1.5	$ (0.9)

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Unrecognized Tax Benefits Net Of Federal Benefits On State Income Tax Positions And Interest

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Amount of decrease in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

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Amount of expense for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return.

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Amount of decrease in unrecognized tax benefits resulting from lapses of applicable statutes of limitations.

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