REVENUE FROM CONTRACTS WITH CUSTOMERS - Schedule of Revenue From Contracts with Customers by Segment (Details) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Net interest income	$ 64,651	$ 60,272
Noninterest income	37,483	37,751
Revenues	102,134	98,023
Refund Transfer Fees
Disaggregation of Revenue [Line Items]
Noninterest income	192	261
Tax Advance Product Fees
Disaggregation of Revenue [Line Items]
Noninterest income	2,276	1,685
Credit Card
Disaggregation of Revenue [Line Items]
Noninterest income	21,499	20,807
Rental income
Disaggregation of Revenue [Line Items]
Noninterest income	487	482
Loan and Lease Fees
Disaggregation of Revenue [Line Items]
Noninterest income	12,351	10,890
Loss on Sale of Securities, Available for Sale
Disaggregation of Revenue [Line Items]
Noninterest income	0	(22)
Gain (Loss) on Other
Disaggregation of Revenue [Line Items]
Noninterest income	(2,568)	1,266
Other Revenues for Financial Assets and Liabilities
Disaggregation of Revenue [Line Items]
Noninterest income	3,246	2,382
Consumer
Disaggregation of Revenue [Line Items]
Net interest income	20,012	13,674
Noninterest income	24,764	22,891
Revenues	44,776	36,565
Consumer | Refund Transfer Fees
Disaggregation of Revenue [Line Items]
Noninterest income	192	261
Consumer | Tax Advance Product Fees
Disaggregation of Revenue [Line Items]
Noninterest income	2,276	1,685
Consumer | Credit Card
Disaggregation of Revenue [Line Items]
Noninterest income	21,499	20,807
Consumer | Rental income
Disaggregation of Revenue [Line Items]
Noninterest income	0	0
Consumer | Loan and Lease Fees
Disaggregation of Revenue [Line Items]
Noninterest income	4	0
Consumer | Loss on Sale of Securities, Available for Sale
Disaggregation of Revenue [Line Items]
Noninterest income	0	0
Consumer | Gain (Loss) on Other
Disaggregation of Revenue [Line Items]
Noninterest income	240	0
Consumer | Other Revenues for Financial Assets and Liabilities
Disaggregation of Revenue [Line Items]
Noninterest income	553	138
Banking
Disaggregation of Revenue [Line Items]
Net interest income	39,736	35,951
Noninterest income	14,980	13,932
Revenues	54,716	49,883
Banking | Refund Transfer Fees
Disaggregation of Revenue [Line Items]
Noninterest income	0	0
Banking | Tax Advance Product Fees
Disaggregation of Revenue [Line Items]
Noninterest income	0	0
Banking | Credit Card
Disaggregation of Revenue [Line Items]
Noninterest income	0	0
Banking | Rental income
Disaggregation of Revenue [Line Items]
Noninterest income	278	293
Banking | Loan and Lease Fees
Disaggregation of Revenue [Line Items]
Noninterest income	11,034	10,890
Banking | Loss on Sale of Securities, Available for Sale
Disaggregation of Revenue [Line Items]
Noninterest income	0	0
Banking | Gain (Loss) on Other
Disaggregation of Revenue [Line Items]
Noninterest income	2,339	1,225
Banking | Other Revenues for Financial Assets and Liabilities
Disaggregation of Revenue [Line Items]
Noninterest income	1,329	1,524
Corporate Services/Other
Disaggregation of Revenue [Line Items]
Net interest income	4,903	10,647
Noninterest income	(2,261)	928
Revenues	2,642	11,575
Corporate Services/Other | Refund Transfer Fees
Disaggregation of Revenue [Line Items]
Noninterest income	0	0
Corporate Services/Other | Tax Advance Product Fees
Disaggregation of Revenue [Line Items]
Noninterest income	0	0
Corporate Services/Other | Credit Card
Disaggregation of Revenue [Line Items]
Noninterest income	0	0
Corporate Services/Other | Rental income
Disaggregation of Revenue [Line Items]
Noninterest income	209	189
Corporate Services/Other | Loan and Lease Fees
Disaggregation of Revenue [Line Items]
Noninterest income	1,313	0
Corporate Services/Other | Loss on Sale of Securities, Available for Sale
Disaggregation of Revenue [Line Items]
Noninterest income	0	(22)
Corporate Services/Other | Gain (Loss) on Other
Disaggregation of Revenue [Line Items]
Noninterest income	(5,147)	41
Corporate Services/Other | Other Revenues for Financial Assets and Liabilities
Disaggregation of Revenue [Line Items]
Noninterest income	$ 1,364	$ 720