LOANS AND LEASES, NET - Nonaccrual (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Sep. 30, 2024
Financing Receivable, Nonaccrual [Line Items]
Total gross loans and leases	$ 4,464,870	$ 4,075,195
Nonaccrual Loans
Financing Receivable, Nonaccrual [Line Items]
2025	0	9,281
2024	4,574	4,748
2023	5,016	5,435
2022	4,970	1,487
2021	15,123	1,369
Prior	4,034	4,063
Revolving Loans and Leases	2,332	29
Total gross loans and leases	36,049	26,412
Nonaccrual with No ACL	12,246	3,260
Nonaccrual Loans \| National Lending \| Term lending
Financing Receivable, Nonaccrual [Line Items]
2025	0	9,281
2024	1,027	3,433
2023	3,058	5,369
2022	4,559	1,386
2021	11,552	625
Prior	2,884	3,368
Revolving Loans and Leases	0	0
Total gross loans and leases	23,080	23,462
Nonaccrual with No ACL	8,109	2,579
Nonaccrual Loans \| National Lending \| Asset-based lending
Financing Receivable, Nonaccrual [Line Items]
2025	0
2024	0
2023	0
2022	0
2021	0
Prior	0
Revolving Loans and Leases	719
Total gross loans and leases	719
Nonaccrual with No ACL	0
Nonaccrual Loans \| National Lending \| Factoring
Financing Receivable, Nonaccrual [Line Items]
2025	0	0
2024	0	0
2023	0	0
2022	0	0
2021	0	0
Prior	0	0
Revolving Loans and Leases	1,613	29
Total gross loans and leases	1,613	29
Nonaccrual with No ACL	0	0
Nonaccrual Loans \| National Lending \| Lease financing
Financing Receivable, Nonaccrual [Line Items]
2025	0	0
2024	0	577
2023	454	11
2022	0	46
2021	3,488	2
Prior	747	110
Revolving Loans and Leases	0	0
Total gross loans and leases	4,689	746
Nonaccrual with No ACL	4,137	0
Nonaccrual Loans \| National Lending \| SBA/USDA
Financing Receivable, Nonaccrual [Line Items]
2025	0	0
2024	3,547	738
2023	1,504	55
2022	411	55
2021	83	742
Prior	403	585
Revolving Loans and Leases	0	0
Total gross loans and leases	5,948	2,175
Nonaccrual with No ACL	0	681
Nonaccrual Loans \| National Lending \| Commercial finance
Financing Receivable, Nonaccrual [Line Items]
2025	0	9,281
2024	4,574	4,748
2023	5,016	5,435
2022	4,970	1,487
2021	15,123	1,369
Prior	4,034	4,063
Revolving Loans and Leases	2,332	29
Total gross loans and leases	36,049	26,412
Nonaccrual with No ACL	12,246	3,260
90 or More Days Delinquent and Accruing
Financing Receivable, Nonaccrual [Line Items]
2025	266	10,500
2024	896	2,481
2023	2,389	1,073
2022	190	809
2021	9	275
Prior	7	12
Revolving Loans and Leases	0	0
Total gross loans and leases	3,757	15,150
90 or More Days Delinquent and Accruing \| Total loans and leases held for investment
Financing Receivable, Nonaccrual [Line Items]
2025	266	9,469
2024	896	2,462
2023	2,389	1,073
2022	190	809
2021	9	275
Prior	7	12
Revolving Loans and Leases	0	0
Total gross loans and leases	3,757	14,100
90 or More Days Delinquent and Accruing \| National Lending \| Loans held for sale
Financing Receivable, Nonaccrual [Line Items]
2025		1,031
2024		19
2023		0
2022		0
2021		0
Prior		0
Revolving Loans and Leases		0
Total gross loans and leases		1,050
90 or More Days Delinquent and Accruing \| National Lending \| Term lending
Financing Receivable, Nonaccrual [Line Items]
2025	0	0
2024	0	621
2023	0	354
2022	0	719
2021	0	217
Prior	7	12
Revolving Loans and Leases	0	0
Total gross loans and leases	7	1,923
90 or More Days Delinquent and Accruing \| National Lending \| Lease financing
Financing Receivable, Nonaccrual [Line Items]
2025		0
2024		0
2023		0
2022		2
2021		58
Prior		0
Revolving Loans and Leases		0
Total gross loans and leases		60
90 or More Days Delinquent and Accruing \| National Lending \| SBA/USDA
Financing Receivable, Nonaccrual [Line Items]
2025	0	0
2024	0	0
2023	1,352	331
2022	0	0
2021	0	0
Prior	0	0
Revolving Loans and Leases	0	0
Total gross loans and leases	1,352	331
90 or More Days Delinquent and Accruing \| National Lending \| Commercial finance
Financing Receivable, Nonaccrual [Line Items]
2025	0	0
2024	0	621
2023	1,352	685
2022	0	721
2021	0	275
Prior	7	12
Revolving Loans and Leases	0	0
Total gross loans and leases	1,359	2,314
90 or More Days Delinquent and Accruing \| National Lending \| Consumer finance
Financing Receivable, Nonaccrual [Line Items]
2025	266	736
2024	896	1,841
2023	1,037	388
2022	190	88
2021	9	0
Prior	0	0
Revolving Loans and Leases	0	0
Total gross loans and leases	$ 2,398	3,053
90 or More Days Delinquent and Accruing \| National Lending \| Tax services
Financing Receivable, Nonaccrual [Line Items]
2025		8,733
2024		0
2023		0
2022		0
2021		0
Prior		0
Revolving Loans and Leases		0
Total gross loans and leases		$ 8,733

Amortized cost excluding accrued interest, before allowance for credit loss, of financing receivable. Excludes net investment in lease.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
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-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479344/326-20-45-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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