Accumulated Other Comprehensive Loss (Details) $ in Thousands	3 Months Ended
	Sep. 30, 2018 USD ($)
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at June 30, 2018	$ (2,313)
Adoption of ASU No. 2016-01	(318)
Other comprehensive income before reclassifications	(854)
Amounts reclassified from accumulated other comprehensive income (loss)	16
Net current period other comprehensive income (loss)	(1,156)
Balance at September 30, 2018	(3,469)
Unrealized Gain / (Loss) on Investments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at June 30, 2018	(1,373)
Adoption of ASU No. 2016-01	(318)
Other comprehensive income before reclassifications	(877)
Amounts reclassified from accumulated other comprehensive income (loss)	0
Net current period other comprehensive income (loss)	(1,195)
Balance at September 30, 2018	(2,568)
Pension and Postretirement Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at June 30, 2018	(1,372)
Adoption of ASU No. 2016-01	0
Other comprehensive income before reclassifications	10
Amounts reclassified from accumulated other comprehensive income (loss)	16
Net current period other comprehensive income (loss)	26
Balance at September 30, 2018	(1,346)
Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance at June 30, 2018	432
Adoption of ASU No. 2016-01	0
Other comprehensive income before reclassifications	13
Amounts reclassified from accumulated other comprehensive income (loss)	0
Net current period other comprehensive income (loss)	13
Balance at September 30, 2018	$ 445