Accumulated Other Comprehensive Loss (Details) $ in Thousands	3 Months Ended
	Sep. 30, 2020 USD ($)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at June 30, 2020	$ (6,206)
Other comprehensive income (loss)	(1,102)
Effect of deferred taxes on unrealized losses	215
Effect of exchange rates on the pension plans	0
Net current period other comprehensive loss	(887)
Balance at September 30, 2020	(7,093)
Pension and Postretirement Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at June 30, 2020	(1,517)
Other comprehensive income (loss)	22
Effect of deferred taxes on unrealized losses	0
Effect of exchange rates on the pension plans	(67)
Net current period other comprehensive loss	(45)
Balance at September 30, 2020	(1,562)
Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at June 30, 2020	523
Other comprehensive income (loss)	(181)
Effect of deferred taxes on unrealized losses	0
Effect of exchange rates on the pension plans	67
Net current period other comprehensive loss	(114)
Balance at September 30, 2020	409
Unrealized Loss on Investments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at June 30, 2020	(5,212)
Other comprehensive income (loss)	(943)
Effect of deferred taxes on unrealized losses	215
Effect of exchange rates on the pension plans	0
Net current period other comprehensive loss	(728)
Balance at September 30, 2020	$ (5,940)