Debt - Schedule of long-term debt outstanding (Details) - USD ($)	Mar. 31, 2021	Mar. 26, 2021	Jul. 10, 2020	Jun. 30, 2020
Debt Instrument [Line Items]
Total	$ 694,300,000			$ 551,800,000
Less: amounts due within one year	0			0
Long-term debt, net of current portion	694,300,000			$ 551,800,000
Senior unsecured notes, 5.20% due July 2021
Debt Instrument [Line Items]
Interest rate				5.20%
Face amount			$ 250,000,000.0	$ 250,000,000.0
Total	$ 0			$ 252,300,000
Senior unsecured notes, 4.45% due March 2023
Debt Instrument [Line Items]
Interest rate	4.45%	4.45%		4.45%
Face amount	$ 300,000,000.0			$ 300,000,000.0
Total	$ 299,400,000	$ 300,000,000.0		299,500,000
Senior unsecured notes, 6.375% due July 2028
Debt Instrument [Line Items]
Interest rate	6.375%		6.375%
Face amount	$ 400,000,000.0		$ 400,000,000
Total	$ 394,900,000			$ 0