LOANS AND LEASES, NET - Nonaccrual (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Sep. 30, 2020
Financing Receivable, Nonaccrual [Line Items]
Loans and leases	$ 3,657,531	$ 3,322,765
Nonaccrual Loans
Financing Receivable, Nonaccrual [Line Items]
2021	72
2020	3,404
2019	11,550
2018	20,944
2017	664
Prior	1,078
Revolving Loans and Leases	417
Loans and leases	38,129
Nonaccrual With No ACL	11,597
Nonaccrual Loans \| National Lending
Financing Receivable, Nonaccrual [Line Items]
2021	72
2020	3,104
2019	10,740
2018	2,785
2017	623
Prior	564
Revolving Loans and Leases	417
Loans and leases	18,305
Nonaccrual With No ACL	9,669
Nonaccrual Loans \| National Lending \| Term lending
Financing Receivable, Nonaccrual [Line Items]
2021	72
2020	2,746
2019	8,834
2018	2,426
2017	23
Prior	564
Revolving Loans and Leases	0
Loans and leases	14,665
Nonaccrual With No ACL	7,942
Nonaccrual Loans \| National Lending \| Asset based lending
Financing Receivable, Nonaccrual [Line Items]
2021	0
2020	0
2019	0
2018	0
2017	0
Prior	0
Revolving Loans and Leases	382
Loans and leases	382
Nonaccrual With No ACL	9
Nonaccrual Loans \| National Lending \| Factoring
Financing Receivable, Nonaccrual [Line Items]
2021	0
2020	0
2019	0
2018	0
2017	0
Prior	0
Revolving Loans and Leases	35
Loans and leases	35
Nonaccrual With No ACL	0
Nonaccrual Loans \| National Lending \| Lease financing
Financing Receivable, Nonaccrual [Line Items]
2021	0
2020	358
2019	1,906
2018	359
2017	0
Prior	0
Revolving Loans and Leases	0
Loans and leases	2,623
Nonaccrual With No ACL	1,118
Nonaccrual Loans \| National Lending \| SBA/USDA
Financing Receivable, Nonaccrual [Line Items]
2021	0
2020	0
2019	0
2018	0
2017	600
Prior	0
Revolving Loans and Leases	0
Loans and leases	600
Nonaccrual With No ACL	600
Nonaccrual Loans \| National Lending \| Commercial finance
Financing Receivable, Nonaccrual [Line Items]
2021	72
2020	3,104
2019	10,740
2018	2,785
2017	623
Prior	564
Revolving Loans and Leases	417
Loans and leases	18,305
Nonaccrual With No ACL	9,669
Nonaccrual Loans \| Community Banking
Financing Receivable, Nonaccrual [Line Items]
2021	0
2020	300
2019	810
2018	18,159
2017	41
Prior	514
Revolving Loans and Leases	0
Loans and leases	19,824
Nonaccrual With No ACL	1,928
Nonaccrual Loans \| Community Banking \| Commercial real estate and operating
Financing Receivable, Nonaccrual [Line Items]
2021	0
2020	300
2019	700
2018	16,896
2017	0
Prior	0
Revolving Loans and Leases	0
Loans and leases	17,896
Nonaccrual With No ACL	0
Nonaccrual Loans \| Community Banking \| Consumer one-to-four family real estate and other
Financing Receivable, Nonaccrual [Line Items]
2021	0
2020	0
2019	110
2018	0
2017	41
Prior	8
Revolving Loans and Leases	0
Loans and leases	159
Nonaccrual With No ACL	159
Nonaccrual Loans \| Community Banking \| Agricultural real estate and operating
Financing Receivable, Nonaccrual [Line Items]
2021	0
2020	0
2019	0
2018	1,263
2017	0
Prior	506
Revolving Loans and Leases	0
Loans and leases	1,769
Nonaccrual With No ACL	1,769
90 or More Days Delinquent and Accruing
Financing Receivable, Nonaccrual [Line Items]
2021	2,560
2020	1,424
2019	139
2018	521
2017	145
Prior	295
Revolving Loans and Leases	0
Loans and leases	5,084
90 or More Days Delinquent and Accruing \| National Lending
Financing Receivable, Nonaccrual [Line Items]
2021	2,560
2020	1,424
2019	139
2018	521
2017	145
Prior	295
Revolving Loans and Leases	0
Loans and leases	5,084
90 or More Days Delinquent and Accruing \| National Lending \| Term lending
Financing Receivable, Nonaccrual [Line Items]
2021	0
2020	0
2019	0
2018	220
2017	112
Prior	21
Revolving Loans and Leases	0
Loans and leases	353
90 or More Days Delinquent and Accruing \| National Lending \| Lease financing
Financing Receivable, Nonaccrual [Line Items]
2021	1,247
2020	323
2019	139
2018	301
2017	33
Prior	0
Revolving Loans and Leases	0
Loans and leases	2,043
90 or More Days Delinquent and Accruing \| National Lending \| Insurance premium finance
Financing Receivable, Nonaccrual [Line Items]
2021	1,313
2020	1,101
2019	0
2018	0
2017	0
Prior	0
Revolving Loans and Leases	0
Loans and leases	2,414
90 or More Days Delinquent and Accruing \| National Lending \| Commercial finance
Financing Receivable, Nonaccrual [Line Items]
2021	2,560
2020	1,424
2019	139
2018	521
2017	145
Prior	21
Revolving Loans and Leases	0
Loans and leases	4,810
90 or More Days Delinquent and Accruing \| National Lending \| Other consumer finance
Financing Receivable, Nonaccrual [Line Items]
2021	0
2020	0
2019	0
2018	0
2017	0
Prior	274
Revolving Loans and Leases	0
Loans and leases	274
90 or More Days Delinquent and Accruing \| National Lending \| Consumer finance
Financing Receivable, Nonaccrual [Line Items]
2021	0
2020	0
2019	0
2018	0
2017	0
Prior	274
Revolving Loans and Leases	0
Loans and leases	$ 274

Amount of financing receivable on nonaccrual status with no allowance for credit loss.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
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