Benefit Plans (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Components of net periodic cost:
Service cost	$ 35	$ 39	$ 71	$ 77
Pension Benefits [Member]
Components of net periodic cost:
Service cost	31	32	62	63
Interest cost	184	173	367	346
Expected return on plan assets	(119)	(115)	(237)	(230)
Recognized net actuarial loss (gain)	106	218	212	436
Amortization of prior service cost	7	21	14	43
Net periodic cost	209	329	418	658
Retiree Health Care Benefits [Member]
Components of net periodic cost:
Service cost	4	7	9	14
Interest cost	13	16	26	32
Expected return on plan assets	0	0	0	0
Recognized net actuarial loss (gain)	(38)	(46)	(77)	(91)
Amortization of prior service cost	(92)	(67)	(184)	(135)
Net periodic cost	$ (113)	$ (90)	$ (226)	$ (180)