SHAREHOLDERS' EQUITY - Components of Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Sep. 30, 2023
After-tax amounts:
Unrealized pension actuarial loss	$ (7,847)	$ (7,981)
Unrealized pension actuarial loss
Pre-tax amounts:
Unrealized pension actuarial loss	(10,233)	(10,407)
After-tax amounts:
Unrealized pension actuarial loss	(7,847)	(7,981)
Accumulated Other Comprehensive Income (Loss)
Pre-tax amounts:
Unrealized pension actuarial loss	(10,233)	(10,407)
After-tax amounts:
Unrealized pension actuarial loss	$ (7,847)	$ (7,981)