Note 10. Accumulated Other Comprehensive Income - Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2019
Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income at beginning of period	$ 2,168	$ 1,976	$ 2,137	$ 1,937
Other Comprehensive Income (Loss) before Reclassifications	82	211	196	315
Reclassification to (earnings) loss	(81)	(67)	(164)	(132)
Net current-period other comprehensive income (loss)	1	144	32	183
Accumulated Other Comprehensive Income at end of period	2,169	2,120	2,169	2,120
Unrealized Investment Gain (Loss)
Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income at beginning of period	14	17	32	23
Other Comprehensive Income (Loss) before Reclassifications	(10)	(9)	(28)	(15)
Reclassification to (earnings) loss	0	0	0	0
Net current-period other comprehensive income (loss)	(10)	(9)	(28)	(15)
Accumulated Other Comprehensive Income at end of period	4	8	4	8
Postemployment Benefits, Net Actuarial Gain (Loss)
Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income at beginning of period	2,154	1,959	2,105	1,914
Other Comprehensive Income (Loss) before Reclassifications	92	220	224	330
Reclassification to (earnings) loss	(81)	(67)	(164)	(132)
Net current-period other comprehensive income (loss)	11	153	60	198
Accumulated Other Comprehensive Income at end of period	$ 2,165	$ 2,112	$ 2,165	$ 2,112