FAIR VALUES OF FINANCIAL INSTRUMENTS - Quantitative Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Minimum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Range of estimated selling cost (in hundredths)	4.00%
Maximum [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Range of estimated selling cost (in hundredths)	10.00%
Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Impaired Loans, Net	$ 2,927,755	$ 1,318,402
Impaired Loans [Member] | Level 3 [Member] | Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Impaired Loans, Net	4,825	0
Foreclosed Assets [Member] | Level 3 [Member] | Valuation, Market Approach [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items] (Deprecated 2018-01-31)
Impaired Loans, Net	$ 31,638	$ 292