Supplemental Cash Flow Information - Schedule of Supplemental Cash Flow Information (Detail) - USD ($) $ in Millions	9 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Jul. 01, 2019
Cash paid during the period for income taxes	$ 0.4	$ 5.3
Cash paid for interest	7.3	$ 9.1
Establishment of operating lease right-of-use assets and lease liabilities
Operating lease right-of-use assets	64.5
Accrued liabilities and other long-term liabilities	4.3
ASU 2016-02
Establishment of operating lease right-of-use assets and lease liabilities
Operating lease right-of-use assets	74.5		$ 74.5
Operating lease liabilities	$ (78.8)		$ (78.8)