LOANS AND LEASES, NET - Past Due Loans (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Sep. 30, 2022
Financing Receivable, Past Due [Line Items]
Loans and leases	$ 4,072,899	$ 3,536,305
Accruing and Nonaccruing Loans and Leases
Financing Receivable, Past Due [Line Items]
Loans and leases	4,155,862	3,550,351
Accruing and Nonaccruing Loans and Leases | Total loans and leases held for investment
Financing Receivable, Past Due [Line Items]
Loans and leases	4,068,511	3,529,280
Accruing and Nonaccruing Loans and Leases | National Lending | Loans held for sale
Financing Receivable, Past Due [Line Items]
Loans and leases	87,351	21,071
Accruing and Nonaccruing Loans and Leases | National Lending | Term lending
Financing Receivable, Past Due [Line Items]
Loans and leases	1,253,841	1,090,289
Accruing and Nonaccruing Loans and Leases | National Lending | Asset based lending
Financing Receivable, Past Due [Line Items]
Loans and leases	373,160	351,696
Accruing and Nonaccruing Loans and Leases | National Lending | Factoring
Financing Receivable, Past Due [Line Items]
Loans and leases	351,133	372,595
Accruing and Nonaccruing Loans and Leases | National Lending | Lease financing
Financing Receivable, Past Due [Line Items]
Loans and leases	201,996	210,692
Accruing and Nonaccruing Loans and Leases | National Lending | Insurance premium finance
Financing Receivable, Past Due [Line Items]
Loans and leases	666,265	479,754
Accruing and Nonaccruing Loans and Leases | National Lending | SBA/USDA
Financing Receivable, Past Due [Line Items]
Loans and leases	422,389	359,238
Accruing and Nonaccruing Loans and Leases | National Lending | Other commercial finance
Financing Receivable, Past Due [Line Items]
Loans and leases	171,954	159,409
Accruing and Nonaccruing Loans and Leases | National Lending | Commercial finance
Financing Receivable, Past Due [Line Items]
Loans and leases	3,440,738	3,023,673
Accruing and Nonaccruing Loans and Leases | National Lending | Consumer credit products
Financing Receivable, Past Due [Line Items]
Loans and leases	175,158	144,353
Accruing and Nonaccruing Loans and Leases | National Lending | Other consumer finance
Financing Receivable, Past Due [Line Items]
Loans and leases	24,963	25,306
Accruing and Nonaccruing Loans and Leases | National Lending | Consumer finance
Financing Receivable, Past Due [Line Items]
Loans and leases	200,121	169,659
Accruing and Nonaccruing Loans and Leases | National Lending | Tax services
Financing Receivable, Past Due [Line Items]
Loans and leases	47,194	9,098
Accruing and Nonaccruing Loans and Leases | National Lending | Warehouse finance
Financing Receivable, Past Due [Line Items]
Loans and leases	380,458	326,850
Accruing and Nonaccruing Loans and Leases | 30-59 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans and leases	37,892	28,203
Accruing and Nonaccruing Loans and Leases | 30-59 Days Past Due | Total loans and leases held for investment
Financing Receivable, Past Due [Line Items]
Loans and leases	37,882	28,203
Accruing and Nonaccruing Loans and Leases | 30-59 Days Past Due | National Lending | Loans held for sale
Financing Receivable, Past Due [Line Items]
Loans and leases	10	0
Accruing and Nonaccruing Loans and Leases | 30-59 Days Past Due | National Lending | Term lending
Financing Receivable, Past Due [Line Items]
Loans and leases	30,464	14,066
Accruing and Nonaccruing Loans and Leases | 30-59 Days Past Due | National Lending | Asset based lending
Financing Receivable, Past Due [Line Items]
Loans and leases	0	0
Accruing and Nonaccruing Loans and Leases | 30-59 Days Past Due | National Lending | Factoring
Financing Receivable, Past Due [Line Items]
Loans and leases	0	0
Accruing and Nonaccruing Loans and Leases | 30-59 Days Past Due | National Lending | Lease financing
Financing Receivable, Past Due [Line Items]
Loans and leases	2,945	8,265
Accruing and Nonaccruing Loans and Leases | 30-59 Days Past Due | National Lending | Insurance premium finance
Financing Receivable, Past Due [Line Items]
Loans and leases	1,884	2,550
Accruing and Nonaccruing Loans and Leases | 30-59 Days Past Due | National Lending | SBA/USDA
Financing Receivable, Past Due [Line Items]
Loans and leases	51	0
Accruing and Nonaccruing Loans and Leases | 30-59 Days Past Due | National Lending | Other commercial finance
Financing Receivable, Past Due [Line Items]
Loans and leases	0	0
Accruing and Nonaccruing Loans and Leases | 30-59 Days Past Due | National Lending | Commercial finance
Financing Receivable, Past Due [Line Items]
Loans and leases	35,344	24,881
Accruing and Nonaccruing Loans and Leases | 30-59 Days Past Due | National Lending | Consumer credit products
Financing Receivable, Past Due [Line Items]
Loans and leases	2,512	3,209
Accruing and Nonaccruing Loans and Leases | 30-59 Days Past Due | National Lending | Other consumer finance
Financing Receivable, Past Due [Line Items]
Loans and leases	26	113
Accruing and Nonaccruing Loans and Leases | 30-59 Days Past Due | National Lending | Consumer finance
Financing Receivable, Past Due [Line Items]
Loans and leases	2,538	3,322
Accruing and Nonaccruing Loans and Leases | 30-59 Days Past Due | National Lending | Tax services
Financing Receivable, Past Due [Line Items]
Loans and leases	0	0
Accruing and Nonaccruing Loans and Leases | 30-59 Days Past Due | National Lending | Warehouse finance
Financing Receivable, Past Due [Line Items]
Loans and leases	0	0
Accruing and Nonaccruing Loans and Leases | 60-89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans and leases	55,178	8,817
Accruing and Nonaccruing Loans and Leases | 60-89 Days Past Due | Total loans and leases held for investment
Financing Receivable, Past Due [Line Items]
Loans and leases	55,178	8,817
Accruing and Nonaccruing Loans and Leases | 60-89 Days Past Due | National Lending | Loans held for sale
Financing Receivable, Past Due [Line Items]
Loans and leases	0	0
Accruing and Nonaccruing Loans and Leases | 60-89 Days Past Due | National Lending | Term lending
Financing Receivable, Past Due [Line Items]
Loans and leases	3,423	2,576
Accruing and Nonaccruing Loans and Leases | 60-89 Days Past Due | National Lending | Asset based lending
Financing Receivable, Past Due [Line Items]
Loans and leases	0	0
Accruing and Nonaccruing Loans and Leases | 60-89 Days Past Due | National Lending | Factoring
Financing Receivable, Past Due [Line Items]
Loans and leases	0	0
Accruing and Nonaccruing Loans and Leases | 60-89 Days Past Due | National Lending | Lease financing
Financing Receivable, Past Due [Line Items]
Loans and leases	729	2,253
Accruing and Nonaccruing Loans and Leases | 60-89 Days Past Due | National Lending | Insurance premium finance
Financing Receivable, Past Due [Line Items]
Loans and leases	874	1,379
Accruing and Nonaccruing Loans and Leases | 60-89 Days Past Due | National Lending | SBA/USDA
Financing Receivable, Past Due [Line Items]
Loans and leases	908	0
Accruing and Nonaccruing Loans and Leases | 60-89 Days Past Due | National Lending | Other commercial finance
Financing Receivable, Past Due [Line Items]
Loans and leases	0	0
Accruing and Nonaccruing Loans and Leases | 60-89 Days Past Due | National Lending | Commercial finance
Financing Receivable, Past Due [Line Items]
Loans and leases	5,934	6,208
Accruing and Nonaccruing Loans and Leases | 60-89 Days Past Due | National Lending | Consumer credit products
Financing Receivable, Past Due [Line Items]
Loans and leases	2,030	2,558
Accruing and Nonaccruing Loans and Leases | 60-89 Days Past Due | National Lending | Other consumer finance
Financing Receivable, Past Due [Line Items]
Loans and leases	20	51
Accruing and Nonaccruing Loans and Leases | 60-89 Days Past Due | National Lending | Consumer finance
Financing Receivable, Past Due [Line Items]
Loans and leases	2,050	2,609
Accruing and Nonaccruing Loans and Leases | 60-89 Days Past Due | National Lending | Tax services
Financing Receivable, Past Due [Line Items]
Loans and leases	47,194	0
Accruing and Nonaccruing Loans and Leases | 60-89 Days Past Due | National Lending | Warehouse finance
Financing Receivable, Past Due [Line Items]
Loans and leases	0	0
Accruing and Nonaccruing Loans and Leases | > 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans and leases	15,807	19,534
Accruing and Nonaccruing Loans and Leases | > 89 Days Past Due | Total loans and leases held for investment
Financing Receivable, Past Due [Line Items]
Loans and leases	15,807	19,534
Accruing and Nonaccruing Loans and Leases | > 89 Days Past Due | National Lending | Loans held for sale
Financing Receivable, Past Due [Line Items]
Loans and leases	0	0
Accruing and Nonaccruing Loans and Leases | > 89 Days Past Due | National Lending | Term lending
Financing Receivable, Past Due [Line Items]
Loans and leases	8,074	4,458
Accruing and Nonaccruing Loans and Leases | > 89 Days Past Due | National Lending | Asset based lending
Financing Receivable, Past Due [Line Items]
Loans and leases	218	68
Accruing and Nonaccruing Loans and Leases | > 89 Days Past Due | National Lending | Factoring
Financing Receivable, Past Due [Line Items]
Loans and leases	0	0
Accruing and Nonaccruing Loans and Leases | > 89 Days Past Due | National Lending | Lease financing
Financing Receivable, Past Due [Line Items]
Loans and leases	1,940	1,714
Accruing and Nonaccruing Loans and Leases | > 89 Days Past Due | National Lending | Insurance premium finance
Financing Receivable, Past Due [Line Items]
Loans and leases	2,394	1,628
Accruing and Nonaccruing Loans and Leases | > 89 Days Past Due | National Lending | SBA/USDA
Financing Receivable, Past Due [Line Items]
Loans and leases	1,002	0
Accruing and Nonaccruing Loans and Leases | > 89 Days Past Due | National Lending | Other commercial finance
Financing Receivable, Past Due [Line Items]
Loans and leases	92	0
Accruing and Nonaccruing Loans and Leases | > 89 Days Past Due | National Lending | Commercial finance
Financing Receivable, Past Due [Line Items]
Loans and leases	13,720	7,868
Accruing and Nonaccruing Loans and Leases | > 89 Days Past Due | National Lending | Consumer credit products
Financing Receivable, Past Due [Line Items]
Loans and leases	2,058	2,669
Accruing and Nonaccruing Loans and Leases | > 89 Days Past Due | National Lending | Other consumer finance
Financing Receivable, Past Due [Line Items]
Loans and leases	29	124
Accruing and Nonaccruing Loans and Leases | > 89 Days Past Due | National Lending | Consumer finance
Financing Receivable, Past Due [Line Items]
Loans and leases	2,087	2,793
Accruing and Nonaccruing Loans and Leases | > 89 Days Past Due | National Lending | Tax services
Financing Receivable, Past Due [Line Items]
Loans and leases	0	8,873
Accruing and Nonaccruing Loans and Leases | > 89 Days Past Due | National Lending | Warehouse finance
Financing Receivable, Past Due [Line Items]
Loans and leases	0	0
Accruing and Nonaccruing Loans and Leases | Total Past Due
Financing Receivable, Past Due [Line Items]
Loans and leases	108,877	56,554
Accruing and Nonaccruing Loans and Leases | Total Past Due | Total loans and leases held for investment
Financing Receivable, Past Due [Line Items]
Loans and leases	108,867	56,554
Accruing and Nonaccruing Loans and Leases | Total Past Due | National Lending | Loans held for sale
Financing Receivable, Past Due [Line Items]
Loans and leases	10	0
Accruing and Nonaccruing Loans and Leases | Total Past Due | National Lending | Term lending
Financing Receivable, Past Due [Line Items]
Loans and leases	41,961	21,100
Accruing and Nonaccruing Loans and Leases | Total Past Due | National Lending | Asset based lending
Financing Receivable, Past Due [Line Items]
Loans and leases	218	68
Accruing and Nonaccruing Loans and Leases | Total Past Due | National Lending | Factoring
Financing Receivable, Past Due [Line Items]
Loans and leases	0	0
Accruing and Nonaccruing Loans and Leases | Total Past Due | National Lending | Lease financing
Financing Receivable, Past Due [Line Items]
Loans and leases	5,614	12,232
Accruing and Nonaccruing Loans and Leases | Total Past Due | National Lending | Insurance premium finance
Financing Receivable, Past Due [Line Items]
Loans and leases	5,152	5,557
Accruing and Nonaccruing Loans and Leases | Total Past Due | National Lending | SBA/USDA
Financing Receivable, Past Due [Line Items]
Loans and leases	1,961	0
Accruing and Nonaccruing Loans and Leases | Total Past Due | National Lending | Other commercial finance
Financing Receivable, Past Due [Line Items]
Loans and leases	92	0
Accruing and Nonaccruing Loans and Leases | Total Past Due | National Lending | Commercial finance
Financing Receivable, Past Due [Line Items]
Loans and leases	54,998	38,957
Accruing and Nonaccruing Loans and Leases | Total Past Due | National Lending | Consumer credit products
Financing Receivable, Past Due [Line Items]
Loans and leases	6,600	8,436
Accruing and Nonaccruing Loans and Leases | Total Past Due | National Lending | Other consumer finance
Financing Receivable, Past Due [Line Items]
Loans and leases	75	288
Accruing and Nonaccruing Loans and Leases | Total Past Due | National Lending | Consumer finance
Financing Receivable, Past Due [Line Items]
Loans and leases	6,675	8,724
Accruing and Nonaccruing Loans and Leases | Total Past Due | National Lending | Tax services
Financing Receivable, Past Due [Line Items]
Loans and leases	47,194	8,873
Accruing and Nonaccruing Loans and Leases | Total Past Due | National Lending | Warehouse finance
Financing Receivable, Past Due [Line Items]
Loans and leases	0	0
Accruing and Nonaccruing Loans and Leases | Current
Financing Receivable, Past Due [Line Items]
Loans and leases	4,046,985	3,493,797
Accruing and Nonaccruing Loans and Leases | Current | Total loans and leases held for investment
Financing Receivable, Past Due [Line Items]
Loans and leases	3,959,644	3,472,726
Accruing and Nonaccruing Loans and Leases | Current | National Lending | Loans held for sale
Financing Receivable, Past Due [Line Items]
Loans and leases	87,341	21,071
Accruing and Nonaccruing Loans and Leases | Current | National Lending | Term lending
Financing Receivable, Past Due [Line Items]
Loans and leases	1,211,880	1,069,189
Accruing and Nonaccruing Loans and Leases | Current | National Lending | Asset based lending
Financing Receivable, Past Due [Line Items]
Loans and leases	372,942	351,628
Accruing and Nonaccruing Loans and Leases | Current | National Lending | Factoring
Financing Receivable, Past Due [Line Items]
Loans and leases	351,133	372,595
Accruing and Nonaccruing Loans and Leases | Current | National Lending | Lease financing
Financing Receivable, Past Due [Line Items]
Loans and leases	196,382	198,460
Accruing and Nonaccruing Loans and Leases | Current | National Lending | Insurance premium finance
Financing Receivable, Past Due [Line Items]
Loans and leases	661,113	474,197
Accruing and Nonaccruing Loans and Leases | Current | National Lending | SBA/USDA
Financing Receivable, Past Due [Line Items]
Loans and leases	420,428	359,238
Accruing and Nonaccruing Loans and Leases | Current | National Lending | Other commercial finance
Financing Receivable, Past Due [Line Items]
Loans and leases	171,862	159,409
Accruing and Nonaccruing Loans and Leases | Current | National Lending | Commercial finance
Financing Receivable, Past Due [Line Items]
Loans and leases	3,385,740	2,984,716
Accruing and Nonaccruing Loans and Leases | Current | National Lending | Consumer credit products
Financing Receivable, Past Due [Line Items]
Loans and leases	168,558	135,917
Accruing and Nonaccruing Loans and Leases | Current | National Lending | Other consumer finance
Financing Receivable, Past Due [Line Items]
Loans and leases	24,888	25,018
Accruing and Nonaccruing Loans and Leases | Current | National Lending | Consumer finance
Financing Receivable, Past Due [Line Items]
Loans and leases	193,446	160,935
Accruing and Nonaccruing Loans and Leases | Current | National Lending | Tax services
Financing Receivable, Past Due [Line Items]
Loans and leases	0	225
Accruing and Nonaccruing Loans and Leases | Current | National Lending | Warehouse finance
Financing Receivable, Past Due [Line Items]
Loans and leases	380,458	326,850
Nonperforming Loans and Leases
Financing Receivable, Past Due [Line Items]
Loans and leases	38,799	29,183
Nonaccrual Balance	30,170	13,375
Nonperforming Loans and Leases | Total loans and leases held for investment
Financing Receivable, Past Due [Line Items]
Loans and leases	38,799	29,183
Nonaccrual Balance	30,170	13,375
Nonperforming Loans and Leases | National Lending | Loans held for sale
Financing Receivable, Past Due [Line Items]
Loans and leases	0	0
Nonaccrual Balance	0	0
Nonperforming Loans and Leases | National Lending | Term lending
Financing Receivable, Past Due [Line Items]
Loans and leases	15,069	9,611
Nonaccrual Balance	13,207	7,576
Nonperforming Loans and Leases | National Lending | Asset based lending
Financing Receivable, Past Due [Line Items]
Loans and leases	14,625	68
Nonaccrual Balance	14,407	29
Nonperforming Loans and Leases | National Lending | Factoring
Financing Receivable, Past Due [Line Items]
Loans and leases	364	569
Nonaccrual Balance	364	569
Nonperforming Loans and Leases | National Lending | Lease financing
Financing Receivable, Past Due [Line Items]
Loans and leases	3,121	4,190
Nonaccrual Balance	1,494	3,750
Nonperforming Loans and Leases | National Lending | Insurance premium finance
Financing Receivable, Past Due [Line Items]
Loans and leases	2,394	1,628
Nonaccrual Balance	0	0
Nonperforming Loans and Leases | National Lending | SBA/USDA
Financing Receivable, Past Due [Line Items]
Loans and leases	1,047	1,451
Nonaccrual Balance	698	1,451
Nonperforming Loans and Leases | National Lending | Other commercial finance
Financing Receivable, Past Due [Line Items]
Loans and leases	92	0
Nonaccrual Balance	0	0
Nonperforming Loans and Leases | National Lending | Commercial finance
Financing Receivable, Past Due [Line Items]
Loans and leases	36,712	17,517
Nonaccrual Balance	30,170	13,375
Nonperforming Loans and Leases | National Lending | Consumer credit products
Financing Receivable, Past Due [Line Items]
Loans and leases	2,058	2,669
Nonaccrual Balance	0	0
Nonperforming Loans and Leases | National Lending | Other consumer finance
Financing Receivable, Past Due [Line Items]
Loans and leases	29	124
Nonaccrual Balance	0	0
Nonperforming Loans and Leases | National Lending | Consumer finance
Financing Receivable, Past Due [Line Items]
Loans and leases	2,087	2,793
Nonaccrual Balance	0	0
Nonperforming Loans and Leases | National Lending | Tax services
Financing Receivable, Past Due [Line Items]
Loans and leases	0	8,873
Nonaccrual Balance	0	0
Nonperforming Loans and Leases | National Lending | Warehouse finance
Financing Receivable, Past Due [Line Items]
Loans and leases	0	0
Nonaccrual Balance	0	0
Nonperforming Loans and Leases | > 89 Days Past Due
Financing Receivable, Past Due [Line Items]
Loans and leases	8,629	15,808
Nonperforming Loans and Leases | > 89 Days Past Due | Total loans and leases held for investment
Financing Receivable, Past Due [Line Items]
Loans and leases	8,629	15,808
Nonperforming Loans and Leases | > 89 Days Past Due | National Lending | Loans held for sale
Financing Receivable, Past Due [Line Items]
Loans and leases	0	0
Nonperforming Loans and Leases | > 89 Days Past Due | National Lending | Term lending
Financing Receivable, Past Due [Line Items]
Loans and leases	1,862	2,035
Nonperforming Loans and Leases | > 89 Days Past Due | National Lending | Asset based lending
Financing Receivable, Past Due [Line Items]
Loans and leases	218	39
Nonperforming Loans and Leases | > 89 Days Past Due | National Lending | Factoring
Financing Receivable, Past Due [Line Items]
Loans and leases	0	0
Nonperforming Loans and Leases | > 89 Days Past Due | National Lending | Lease financing
Financing Receivable, Past Due [Line Items]
Loans and leases	1,627	440
Nonperforming Loans and Leases | > 89 Days Past Due | National Lending | Insurance premium finance
Financing Receivable, Past Due [Line Items]
Loans and leases	2,394	1,628
Nonperforming Loans and Leases | > 89 Days Past Due | National Lending | SBA/USDA
Financing Receivable, Past Due [Line Items]
Loans and leases	349	0
Nonperforming Loans and Leases | > 89 Days Past Due | National Lending | Other commercial finance
Financing Receivable, Past Due [Line Items]
Loans and leases	92	0
Nonperforming Loans and Leases | > 89 Days Past Due | National Lending | Commercial finance
Financing Receivable, Past Due [Line Items]
Loans and leases	6,542	4,142
Nonperforming Loans and Leases | > 89 Days Past Due | National Lending | Consumer credit products
Financing Receivable, Past Due [Line Items]
Loans and leases	2,058	2,669
Nonperforming Loans and Leases | > 89 Days Past Due | National Lending | Other consumer finance
Financing Receivable, Past Due [Line Items]
Loans and leases	29	124
Nonperforming Loans and Leases | > 89 Days Past Due | National Lending | Consumer finance
Financing Receivable, Past Due [Line Items]
Loans and leases	2,087	2,793
Nonperforming Loans and Leases | > 89 Days Past Due | National Lending | Tax services
Financing Receivable, Past Due [Line Items]
Loans and leases	0	8,873
Nonperforming Loans and Leases | > 89 Days Past Due | National Lending | Warehouse finance
Financing Receivable, Past Due [Line Items]
Loans and leases	$ 0	$ 0