Accumulated Other Comprehensive Income- Schedule of Balances of Each Component (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2021	Dec. 31, 2020
Accumulated Other Comprehensive Income
Balance at the beginning of the period	$ 230,519	$ 247,693	$ 239,670	$ 244,796
Other comprehensive income (loss) before reclassifications	558	82	493	196
Reclassification to (earnings) loss	(44)	(81)	(102)	(164)
Net current-period other comprehensive income (loss)	514	1	391	32
Balance at the end of the period	206,664	244,012	206,664	244,012
Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income
Balance at the beginning of the period	1,857	2,168	1,980	2,137
Balance at the end of the period	2,371	2,169	2,371	2,169
Unrealized Investment Gain (Loss)
Accumulated Other Comprehensive Income
Balance at the beginning of the period	0	14	0	32
Other comprehensive income (loss) before reclassifications	0	(10)	0	(28)
Reclassification to (earnings) loss	0	0	0	0
Net current-period other comprehensive income (loss)	0	(10)	0	(28)
Balance at the end of the period	0	4	0	4
Postemployment Benefits Net Actuarial Gain (Loss)
Accumulated Other Comprehensive Income
Balance at the beginning of the period	2,075	2,154	1,980	2,105
Other comprehensive income (loss) before reclassifications	222	92	418	224
Reclassification to (earnings) loss	(100)	(81)	(201)	(164)
Net current-period other comprehensive income (loss)	122	11	217	60
Balance at the end of the period	2,197	2,165	2,197	2,165
Interest Rate Swap Gain (Loss)
Accumulated Other Comprehensive Income
Balance at the beginning of the period	(218)	0	0	0
Other comprehensive income (loss) before reclassifications	336	0	75	0
Reclassification to (earnings) loss	56	0	99	0
Net current-period other comprehensive income (loss)	392	0	174	0
Balance at the end of the period	$ 174	$ 0	$ 174	$ 0