Note 7. Accumulated Other Comprehensive Income - Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income at beginning of period	$ 1,788	$ 1,246	$ 1,816	$ 1,115
Other Comprehensive Income (Loss) before Reclassifications	145	128	179	300
Reclassification to (earnings) loss	(72)	(47)	(134)	(88)
Net current-period other comprehensive income (loss)	73	81	45	212
Accumulated Other Comprehensive Income at end of period	1,861	1,327	1,861	1,327
Unrealized Investment Gain (Loss)
Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income at beginning of period	(50)	(12)	(31)	(21)
Other Comprehensive Income (Loss) before Reclassifications	30	(27)	11	(18)
Reclassification to (earnings) loss	0	2	0	2
Net current-period other comprehensive income (loss)	30	(25)	11	(16)
Accumulated Other Comprehensive Income at end of period	(20)	(37)	(20)	(37)
Postemployment Benefits, Net Actuarial Gain (Loss)
Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income at beginning of period	1,840	1,258	1,854	1,136
Other Comprehensive Income (Loss) before Reclassifications	117	155	177	318
Reclassification to (earnings) loss	(76)	(49)	(150)	(90)
Net current-period other comprehensive income (loss)	41	106	27	228
Accumulated Other Comprehensive Income at end of period	1,881	1,364	1,881	1,364
Derivative Gain (Loss)
Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income at beginning of period	(2)	0	(7)	0
Other Comprehensive Income (Loss) before Reclassifications	(2)	0	(9)	0
Reclassification to (earnings) loss	4	0	16	0
Net current-period other comprehensive income (loss)	2	0	7	0
Accumulated Other Comprehensive Income at end of period	$ 0	$ 0	$ 0	$ 0