Short-Term and Long-Term Debt - Narrative (Details)	3 Months Ended		9 Months Ended
	Mar. 31, 2021 USD ($)	Mar. 31, 2020 USD ($)	Mar. 31, 2021 USD ($)	Mar. 31, 2020 USD ($)
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 125,000,000.0		$ 125,000,000.0
Maximum borrowing capacity upon request	200,000,000.0		200,000,000.0
Amount available for letters of credit	10,000,000		10,000,000
Line of credit facility, remaining borrowing capacity	83,300,000		83,300,000
Interest paid on borrowings	182,000	$ 0	211,000	$ 15,000
Adjusted leverage ratio, indebtedness reduction for excess cash	$ 15,000,000		$ 15,000,000
Adjusted leverage ratio covenant	3.0		3.0
Interest coverage ratio covenant	3.00		3.00
London Interbank Offered Rate (LIBOR) | Primary Revolving Credit Facility
Debt Instrument [Line Items]
Interest rate charged over index rate			1.00%
Federal Funds Rate
Debt Instrument [Line Items]
Interest rate charged over index rate			0.50%
Minimum | Eurocurrency Loans Margin
Debt Instrument [Line Items]
Interest rate (basis points)			0.01250
Minimum | Alternate Base Rate Loans Spread
Debt Instrument [Line Items]
Interest rate (basis points)			0.00250
Maximum
Debt Instrument [Line Items]
Adjusted leverage ratio, indebtedness reduction for excess cash	$ 35,000,000		$ 35,000,000
Maximum | Eurocurrency Loans Margin
Debt Instrument [Line Items]
Interest rate (basis points)			0.02000
Maximum | Alternate Base Rate Loans Spread
Debt Instrument [Line Items]
Interest rate (basis points)			0.01000
Financial Standby Letter of Credit
Debt Instrument [Line Items]
Letters of credit, amount	$ 1,700,000		$ 1,700,000