Other Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Jun. 30, 2020
Payables and Accruals [Abstract]
Accrued postretirement benefits	$ 617	$ 744
Accrued workers’ compensation liabilities	1,145	1,466
Liability, Defined Benefit Plan, Current	1,619	1,477
Working capital dispute payable	551	551
Other (including net taxes payable)	2,692	2,564
Other current liabilities	$ 6,624	$ 6,802