EMPLOYEE BENEFIT PLANS (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016	Jan. 01, 2018
EMPLOYEE BENEFIT PLANS (Details) [Line Items]
Defined contribution plan, employer discretionary contribution amount	$ 8,328	$ 8,714	$ 8,301
Postemployment benefits liability	$ 1,699	2,014
Change in discount rate	10.00%
Tax benefit for amortization of pension cost	$ 342	1,170	831
Defined benefit plan, actuarial gain (loss)	887
Service cost	$ 14
Adjusted funding target attainment percent				95.80%
Adjusted funding target attainment percent, threshold				80.00%
Defined benefit plan, target plan asset allocations	100.00%
Defined benefit plans, estimated future employer contributions in next fiscal year	$ 1,100
Completion period of service	1 year
Maximum compensation of proportion	$ 275
Employee stock ownership plan (ESOP), compensation expense	9,532	5,643	$ 3,689
Employee stock ownership plan (ESOP), deferred shares, fair value	47,916	69,394
Other Postretirement Benefits Plan [Member]
EMPLOYEE BENEFIT PLANS (Details) [Line Items]
Accumulated other comprehensive income (loss), pension and other postretirement benefit plans, net of tax	(60)	(107)
Pension and other postretirement benefit expense	45	41
Supplemental Employee Retirement Plan [Member]
EMPLOYEE BENEFIT PLANS (Details) [Line Items]
Accumulated other comprehensive income (loss), pension and other postretirement benefit plans, net of tax	(3,396)	(12,601)
Company contributions	3,001	4,057
Defined benefit plan, actuarial gain (loss)	14,452	(195)
Defined benefit plan, expected future benefit payments, next twelve months	1,906
Pension Plan [Member]
EMPLOYEE BENEFIT PLANS (Details) [Line Items]
Accumulated other comprehensive income (loss), pension and other postretirement benefit plans, net of tax	(12,985)	(15,539)
Company contributions	2,449	3,747
Defined benefit plan, actuarial gain (loss)	7,562	$ 9,318
Defined benefit plan, expected future benefit payments, next twelve months	10,767
Defined Benefit Plan, Expected Future Employer Contributions, Current Fiscal Year	$ 3,114