Other Current Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Jun. 30, 2019
Payables and Accruals [Abstract]
Accrued postretirement benefits	$ 1,068	$ 1,068
Accrued workers’ compensation liabilities	1,681	1,495
Liability, Defined Benefit Plan, Current	1,198	305
Earnout payable	0	1,000
Working capital dispute payable	354	354
Other (including net taxes payable)	3,681	3,087
Other current liabilities	$ 7,982	$ 7,309