EMPLOYEE STOCK OWNERSHIP AND PROFIT SHARING PLANS (Details) - USD ($)	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
EMPLOYEE STOCK OWNERSHIP AND PROFIT SHARING PLANS [Abstract]
Number of hours of employment required for ESOP	1000 hours
Years of employment to be eligible for ESOP	1 year
Eligible age for ESOP	21 years
Employee Stock Ownership Plan (ESOP), Expense	$ 1,668,000	$ 1,150,000	$ 994,000
Contribution to ESOP	$ 1,606,102	$ 1,174,682	$ 992,038
Percentage of benefits vested after credited service	100.00%
ESOP award vesting period	7 years
Years of credited service	7 years
Number of shares (ESOP) released (in shares)	20,486	19,381	23,750
Fair value of shares (ESOP) released (in dollars per share)	$ 78.40	$ 60.61	$ 41.77
Allocated and total ESOP shares withdrawn from ESOP by participant no longer with the company (in shares)	14,126	15,502	10,294
Shares purchased for dividend reinvestment (in shares)	1,479	2,710	2,974
Year-end ESOP shares [Abstract]
Allocated shares (in shares)	256,219	262,872	256,283
Unearned shares (in shares)	0	0	0
Total ESOP shares (in shares)	256,219	262,872	256,283
Fair value of unearned shares	$ 0	$ 0	$ 0
Contribution expense to profit sharing plan included in compensation and benefits	$ 1,610,000	$ 1,260,000	$ 1,100,000