SIGNIFICANT EVENTS - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Loss Contingencies [Line Items]
Provision for loan and lease losses	$ 15,093	$ 9,112	$ 55,796	$ 51,529
COVID-19 Pandemic
Loss Contingencies [Line Items]
Short-term payment deferral modifications			352,100
Loans and leases still in deferment period	292,200		292,200
Short-term payment deferral modifications, interest rate deferral modification			52,900
Active loans	34,600		34,600
Provision for loan and lease losses	$ 9,400		$ 25,200