OTHER COMPREHENSIVE INCOME - Balances and Changes in AOCI (Details) - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Accumulated other comprehensive income (loss)
Balance at beginning of period	$ 134,965	$ 118,063
Balance at end of period	223,966	134,965
Accumulated Other Comprehensive Loss
Accumulated other comprehensive income (loss)
Balance at beginning of period	(11,103)	(8,989)
Other comprehensive income (loss) before reclassifications	(7,079)	(2,671)
Amounts reclassified from accumulated other comprehensive (loss) income	696	557
Reclassification for change in accounting principle	116
Balance at end of period	(17,370)	(11,103)
Unrealized Gains/Losses on Securities
Accumulated other comprehensive income (loss)
Balance at beginning of period	338	410
Other comprehensive income (loss) before reclassifications	28	(67)
Amounts reclassified from accumulated other comprehensive (loss) income	(102)	(5)
Reclassification for change in accounting principle	116
Balance at end of period	380	338
Defined Benefit Plan
Accumulated other comprehensive income (loss)
Balance at beginning of period	(11,441)	(9,399)
Other comprehensive income (loss) before reclassifications	(7,107)	(2,604)
Amounts reclassified from accumulated other comprehensive (loss) income	798	562
Balance at end of period	$ (17,750)	$ (11,441)