Debt - Schedule of Long-term Debt Outstanding (Details) - USD ($)	Jun. 30, 2020	Jun. 30, 2019
Revolving Credit Agreement
Long-term debt, net of current portion	$ 551,800,000	$ 550,600,000
Senior Notes
Revolving Credit Agreement
Total	551,800,000	550,600,000
Less: amounts due within one year	0	0
Long-term debt, net of current portion	$ 551,800,000	550,600,000
Senior Notes \| Senior unsecured notes, 5.20% due July 2021 (face value of $250.0 million at June 30, 2020 and 2019)
Revolving Credit Agreement
Interest rate	5.20%
Face amount	$ 250,000,000.0	250,000,000.0
Total	$ 252,300,000	251,200,000
Senior Notes \| Senior unsecured notes, 4.45% due March 2023 (face value of $300.0 million at June 30, 2020 and 2019)
Revolving Credit Agreement
Interest rate	4.45%
Face amount	$ 300,000,000.0	300,000,000.0
Total	$ 299,500,000	$ 299,400,000

Face (par) amount of debt instrument at time of issuance.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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