Benefit Plans (Details) - USD ($) $ in Thousands	3 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Pension Benefits [Member]
Components of net periodic cost:
Service cost	$ 11	$ 31
Interest cost	174	183
Expected return on plan assets	(133)	(118)
Recognized net actuarial loss (gain)	46	106
Amortization of prior service cost	0	7
Net periodic cost (benefit)	98	209
Postretirement Health Coverage [Member]
Components of net periodic cost:
Service cost	4	5
Interest cost	13	13
Expected return on plan assets	0	0
Recognized net actuarial loss (gain)	(30)	(39)
Amortization of prior service cost	(92)	(92)
Net periodic cost (benefit)	$ (105)	$ (113)