EMPLOYEE BENEFIT PLANS - Net Periodic Post-retirement Benefit Cost (Details) - Post-retirement benefit plan - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Net periodic post-retirement benefit cost
Service cost	$ 9	$ 7	$ 27	$ 21
Interest cost	16	17	48	50
Amortization of net actuarial loss	1		2
Net periodic cost	$ 26	$ 24	$ 77	$ 71