LOANS AND LEASES, NET - Additional Information (Details) - USD ($)	12 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases to held for sale	$ 169,045,000	$ 188,638,000	$ 542,101,000
Originations of loans held-for-sale	985,330,000	601,481,000	$ 98,798,000
Proceeds from held-for-sale loans	1,060,000,000.00	890,300,000
Gain on sale of held for sale loans	3,700,000	8,600,000
Loans and leases	3,536,305,000	3,609,563,000
Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	2,548,929,000	2,468,557,000
Asset Pledged as Collateral | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	120,700,000
Community Bank
Accounts, Notes, Loans and Financing Receivable [Line Items]
Servicing fee expense	200,000	3,300,000
Additional loans sold	$ 192,500,000	308,100,000
Covid-19 Pandemic
Accounts, Notes, Loans and Financing Receivable [Line Items]
Trial modifications, threshold of past due days prior to onset of pandemic effects	30 days
Loans and lease receivables deferred income	$ 0
Covid-19 Pandemic | Minimum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Trial modifications, payment deferral period	30 days
Covid-19 Pandemic | Maximum
Accounts, Notes, Loans and Financing Receivable [Line Items]
Trial modifications, payment deferral period	6 months
Community Banking | Pass
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases		10,314,000
Other Consumer Finance and SBA/USDA Loans | National Lending
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originations of loans held-for-sale	$ 985,300,000
Other Consumer Finance, SBA/USDA and Consumer Credit Product Loans | National Lending
Accounts, Notes, Loans and Financing Receivable [Line Items]
Originations of loans held-for-sale		601,500,000
Tax services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	9,100,000	10,400,000
Commercial finance | National Lending
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, TDR, postmodification	10,500,000	5,900,000
Loans modified in TDR, subsequent default	5,200,000	3,400,000
Consumer finance
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	169,700,000	252,900,000
Consumer finance | National Lending
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, TDR, postmodification	900,000	300,000
Loans modified in TDR, subsequent default	$ 1,100,000	$ 300,000