SECURITIES - Held to Maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Sep. 30, 2019
Debt Securities, Held-to-maturity, Fair Value to Amortized Cost [Abstract]
Amortized Cost	$ 123,117	$ 134,764
Gross unrealized gains	106	122
Gross unrealized (losses)	(1,324)	(1,416)
Debt securities held to maturity	121,899	133,470
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position [Abstract]
LESS THAN 12 MONTHS, Fair Value	9,211	7,438
LESS THAN 12 MONTHS, Unrealized (Losses)	(16)	(6)
OVER 12 MONTHS, Fair Value	100,834	111,171
OVER 12 MONTHS, Unrealized (Losses)	(1,308)	(1,410)
TOTAL, Fair Value	110,045	118,609
TOTAL, Unrealized (Losses)	(1,324)	(1,416)
Amortized Cost
Due after ten years	116,313	127,582
Total	116,313	127,582
Mortgage-backed securities	6,804	7,182
Total securities HTM, at cost	123,117	134,764
Fair Value
Due after ten years	115,125	126,287
Total	115,125	126,287
Mortgage-backed securities	6,774	7,183
Total held to maturity securities	121,899	133,470
Non-bank Qualified Obligations of States and Political Subdivisions
Debt Securities, Held-to-maturity, Fair Value to Amortized Cost [Abstract]
Amortized Cost	116,313	127,582
Gross unrealized gains	104	108
Gross unrealized (losses)	(1,292)	(1,403)
Debt securities held to maturity	115,125	126,287
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position [Abstract]
LESS THAN 12 MONTHS, Fair Value	5,686	5,967
LESS THAN 12 MONTHS, Unrealized (Losses)	(3)	(6)
OVER 12 MONTHS, Fair Value	99,199	109,368
OVER 12 MONTHS, Unrealized (Losses)	(1,289)	(1,397)
TOTAL, Fair Value	104,885	115,335
TOTAL, Unrealized (Losses)	(1,292)	(1,403)
Amortized Cost
Total securities HTM, at cost	116,313	127,582
Fair Value
Total held to maturity securities	115,125	126,287
Mortgage-backed Securities
Debt Securities, Held-to-maturity, Fair Value to Amortized Cost [Abstract]
Amortized Cost	6,804	7,182
Gross unrealized gains	2	14
Gross unrealized (losses)	(32)	(13)
Debt securities held to maturity	6,774	7,183
Debt Securities, Held-to-maturity, Continuous Unrealized Loss Position [Abstract]
LESS THAN 12 MONTHS, Fair Value	3,525	1,471
LESS THAN 12 MONTHS, Unrealized (Losses)	(13)	0
OVER 12 MONTHS, Fair Value	1,635	1,803
OVER 12 MONTHS, Unrealized (Losses)	(19)	(13)
TOTAL, Fair Value	5,160	3,274
TOTAL, Unrealized (Losses)	(32)	(13)
Amortized Cost
Total securities HTM, at cost	6,804	7,182
Fair Value
Total held to maturity securities	$ 6,774	$ 7,183

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