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EMPLOYEE BENEFIT PLANS - Narrative (Details) - USD ($) $ in Thousands | 12 Months Ended |
--- | --- | ---
Sep. 30, 2021 | Sep. 30, 2020 | Sep. 30, 2019 | Jan. 01, 2021
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |  |
Defined contribution plan, employer discretionary contribution amount | $ 8,576 | $ 6,855 | $ 7,097 |
Postemployment benefits liability | 1,678 | 1,833 |  |
Non-service cost components of net periodic benefit cost (credit) | $ (907) | (1,559) | (3,148) |
Change in discount rate | 10.00% |  |  |
Tax benefit for amortization of pension cost | $ 270 | 878 | 221 |
Completion period of service | 1 year |  |  |
Maximum compensation of proportion | $ 290 |  |  |
Employee stock ownership plan (ESOP), compensation expense | 3,678 | 2,878 | $ 2,629 |
Employee stock ownership plan (ESOP), deferred shares, fair value | 45,571 | 40,217 |  |
Clopay AMES Plan |  |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |  |
Adjusted funding target attainment percent |  |  |  | 98.70%
Adjusted funding target attainment percent, threshold |  |  |  | 80.00%
Defined benefit plans, estimated future employer catch up contributions in next fiscal year | 198 |  |  |
Other Postretirement Benefits Plan |  |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |  |
Accumulated other comprehensive income (loss), pension and other postretirement benefit plans, net of tax | (118) | (196) |  |
Pension and other postretirement benefit expense | 35 | 46 |  |
Supplemental Employee Retirement Plan |  |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |  |
Accumulated other comprehensive income (loss), pension and other postretirement benefit plans, net of tax | (6,053) | (6,083) |  |
Defined benefit plans, estimated future employer contributions in next fiscal year | 1,884 |  |  |
Pension Plan |  |  |  |
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |  |  |  |
Accumulated other comprehensive income (loss), pension and other postretirement benefit plans, net of tax | (30,254) | $ (48,716) |  |
Defined benefit plans, estimated future employer contributions in next fiscal year | $ 953 |  |  |

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