Employee Retirement Benefits - Additional Information (Details) - USD ($)	12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2018
Employee Retirement Benefits
Contribution to retirement savings plan	$ 185,000	$ 190,965	$ 197,999
Percentage of eligible salaried employees annual income	2.00%
Percentage of annual income to plan	25.00%
Percentage of employee deferrals	8.00%