PREMISES, FURNITURE, AND EQUIPMENT, NET (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Property, Plant and Equipment [Line Items]
Premises, furniture, and equipment, gross	$ 79,285	$ 99,212
Less: accumulated depreciation and amortization	(37,575)	(54,324)
Net book value	41,710	44,888
Depreciation expense of premises, furniture, and equipment	11,300	9,600	$ 9,200
Land
Property, Plant and Equipment [Line Items]
Premises, furniture, and equipment, gross	1,354	1,354
Buildings
Property, Plant and Equipment [Line Items]
Premises, furniture, and equipment, gross	21,300	21,196
Furniture, Fixtures, and Equipment
Property, Plant and Equipment [Line Items]
Premises, furniture, and equipment, gross	$ 56,631	$ 76,662