Employee Deferred Savings Plan - Company Recorded Contributions To Plan (Detail) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Compensation And Retirement Disclosure [Abstract]
Deferred savings plan contributions	$ 2.2	$ 2.3	$ 6.8	$ 6.0

Amount of contribution received by defined benefit plan from employer which increases plan assets.

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Name:	us-gaap_DefinedBenefitPlanContributionsByEmployer
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration