LOANS AND LEASES, NET - Direct Financing and Sales-type Leases, and Lease Receivable Maturity (Details) - USD ($) $ in Thousands	3 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Sep. 30, 2020
Net Investment in Lease [Abstract]
Carrying Amount	$ 300,748		$ 299,487
Unguaranteed residual assets	17,488		17,203
Unamortized initial direct costs	2,056		2,078
Unearned income	(34,514)		(35,606)
Total net investment in direct financing and sales-type leases	285,778		$ 283,162
Operating Lease, Lease Income [Abstract]
Interest income on net investments in direct financing and sales-type leases	5,319	$ 4,087
Lease income from operating lease payments	10,041	11,203
Profit (loss) recorded on commencement date on sales-type leases	71	471
Other	69	750
Total leasing and equipment finance noninterest income	10,181	12,424
Total lease income	15,500	$ 16,511
Sales-type and Direct Financing Leases, Lease Receivable, Fiscal Year Maturity [Abstract]
Remaining in 2021	85,352
2022	95,224
2023	66,168
2024	36,759
2025	13,669
Thereafter	3,576
Equipment under leases not yet commenced	0
Total undiscounted future minimum lease payments receivable for direct financing and sales-type leases	300,748
Third-party residual value guarantees	0
Total carrying amount of direct financing and sales-type leases	$ 300,748

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Leasing and Equipment Finance, Non-interest Income

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Amount of other addition (reduction) in allowance reserve for credit loss.

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Amount of lease income from operating, direct financing, and sales-type leases. Includes, but is not limited to, variable lease payments, interest income, profit (loss) recognized at commencement, and lease payments paid and payable to lessor.

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Amount of operating lease income from lease payments paid and payable to lessor. Excludes variable lease payments not included in measurement of lease receivable.

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Amount of residual asset covered by residual value guarantee. Excludes guarantee considered to be lease payments for lessor.

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Present value of lease payments not yet received by lessor and amount expected to be derived from underlying asset, following end of lease term guaranteed by lessee or other third party unrelated to lessor, from sales-type and direct financing leases.

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Amount of undiscounted cash flows to be received by lessor for sales-type and direct financing leases.

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Amount of undiscounted cash flows to be received by lessor for sales-type and direct financing leases in fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of undiscounted lease receivable in excess of discounted receivable for sales-type and direct financing leases.

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Present value expected to be derived from underlying asset following end of lease term not guaranteed by lessee or other third party unrelated to lessor.

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