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STOCKHOLDERS' EQUITY AND EQUITY COMPENSATION - Narrative (Details) $ / shares in Units, $ in Thousands |  |  |  |  |  |  | 12 Months Ended |  |
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Nov. 18, 2025 USD ($) executive $ / shares shares | Nov. 12, 2024 USD ($) | Mar. 20, 2024 shares | Feb. 20, 2024 USD ($) $ / shares shares | Sep. 05, 2023 $ / shares shares | Feb. 17, 2022 shares | Sep. 30, 2025 USD ($) executive $ / shares shares | Sep. 30, 2024 USD ($) $ / shares | Sep. 30, 2023 USD ($) $ / shares | Jan. 30, 2020 shares | Jan. 31, 2018 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |
Accrued dividends | $ |  |  |  |  |  |  | $ 2,962 |  |  |  |
Share-based payment award, number of shares authorized (in shares) |  |  |  |  |  |  | 3,527,590 |  |  |  |
Number of additional shares authorized (in shares) |  |  |  |  |  | 1,200,000 |  |  |  |  |
Number of shares issued out of treasury stock (in shares) |  |  |  |  |  |  | 590,366 |  |  |  |
Stock repurchase program, authorized amount, period income (decrease) | $ |  | $ 400,000 |  |  |  |  |  |  |  |  |
Stock repurchased during period (in shares) |  |  |  | 1,500,000 |  |  | 1,897,182 |  |  |  |
Stock repurchased during period | $ |  |  |  | $ 98,250 |  |  | $ 134,680 |  |  |  |
Shares acquired, average cost per share (in dollars per share) | $ / shares |  |  |  | $ 65.50 |  |  | $ 70.99 |  |  |  |
Excise tax price | $ |  |  |  |  |  |  | $ 1,329 |  |  |  |
Stock repurchase program, remaining authorized repurchase amount | $ |  |  |  |  |  |  | $ 298,013 |  |  |  |
Common stock, par value (in dollars per share) | $ / shares |  |  |  | $ 0.25 |  |  | $ 0.25 | $ 0.25 |  |  |
Shares paid for tax withholding for share based compensation (in shares) |  |  |  |  |  |  | 583,978 |  |  |  |
Shares paid for tax withholding for share based compensation, value | $ |  |  |  |  |  |  | $ 45,284 |  |  |  |
Shares paid for tax withholding for share based compensation, value per share (in dollars per share) | $ / shares |  |  |  |  |  |  | $ 77.54 |  |  |  |
Reversal of excise taxes to adjust for a benefit related to employee vesting | $ |  |  |  |  |  |  | $ (528) |  |  |  |
Share repurchase program, employee vesting | $ |  |  |  |  |  |  | (107) |  |  |  |
Stock repurchase program, exercise tax accrued | $ |  |  |  |  |  |  | $ 694 |  |  |  |
Voss Capital, LLC | Related Party |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |
Stock repurchased during period (in shares) |  |  |  |  | 400,000 |  | 1,500,000 |  |  |  |
Shares acquired, average cost per share (in dollars per share) | $ / shares |  |  |  |  | $ 41.87 |  | $ 65.50 |  |  |  |
Common stock, par value (in dollars per share) | $ / shares |  |  |  |  | $ 0.25 |  | $ 0.25 |  |  |  |
Stock repurchase program, authorized amount | $ |  |  |  |  |  |  | $ 98,250 |  |  |  |
Restricted Stock, Subject to Performance Conditions | Executive Officer and Key Employees |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |
Instruments grants in period (in shares) |  |  |  |  |  |  | 137,479 |  |  |  |
Restricted Stock, Subject to Performance Conditions | Senior Executives |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of recipients of stock-based compensation award | executive |  |  |  |  |  |  | 4 |  |  |  |
Share-based payment award, award vesting period |  |  |  |  |  |  | 36 months |  |  |  |
Instruments grants in period (in shares) |  |  |  |  |  |  | 436,947 |  |  |  |
Equity instruments other than options, granted in period, fair value | $ |  |  |  |  |  |  | $ 12,372 |  |  |  |
Granted (in dollars per share) | $ / shares |  |  |  |  |  |  | $ 84.95 |  |  |  |
Post-vesting holding period |  |  |  |  |  |  | 2 years |  |  |  |
Restricted Stock, Subject to Performance Conditions | Senior Executives | Minimum |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of shares to be vested if performance condition is attained (in shares) |  |  |  |  |  |  | 72,827 |  |  |  |
Target number of shares to be vested if performance condition is attained (in shares) |  |  |  |  |  |  | 145,649 |  |  |  |
Restricted Stock, Subject to Performance Conditions | Senior Executives | Maximum |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of shares to be vested if performance condition is attained (in shares) |  |  |  |  |  |  | 436,947 |  |  |  |
Restricted Stock and Restricted Stock Units |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |
Share-based payment award, award vesting period |  |  |  |  |  |  | 3 years |  |  |  |
Instruments grants in period (in shares) |  |  |  |  |  |  | 579,858 |  |  |  |
Restricted Stock and Restricted Stock Units | Director |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |
Share-based payment award, award vesting period |  |  |  |  |  |  | 1 year |  |  |  |
Instruments grants in period (in shares) |  |  |  |  |  |  | 15,940 |  |  |  |
Equity instruments other than options, granted in period, fair value | $ |  |  |  |  |  |  | $ 1,100 |  |  |  |
Granted (in dollars per share) | $ / shares |  |  |  |  |  |  | $ 69.03 |  |  |  |
Restricted Stock |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |
Share-based payment award, options, vested in period, fair value | $ |  |  |  |  |  |  | $ 97,833 | $ 80,861 | $ 25,863 |  |
Employee service share-based compensation, nonvested awards, compensation not yet recognized, share-based awards other than options | $ |  |  |  |  |  |  | $ 37,911 |  |  |  |
Employee service share-based compensation, nonvested awards, compensation cost not yet recognized, period for recognition |  |  |  |  |  |  | 1 year 9 months 18 days |  |  |  |
Instruments grants in period (in shares) |  |  |  |  |  |  | 595,798 |  |  |  |
Granted (in dollars per share) | $ / shares |  |  |  |  |  |  | $ 81.30 |  |  |  |
Restricted Stock Units (RSUs), Subject to Performance Conditions | Executive Officer and Key Employees |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of recipients of stock-based compensation award | executive |  |  |  |  |  |  | 43 |  |  |  |
Share-based payment award, award vesting period |  |  |  |  |  |  | 36 months |  |  |  |
Instruments grants in period (in shares) |  |  |  |  |  |  | 5,432 |  |  |  |
Equity instruments other than options, granted in period, fair value | $ |  |  |  |  |  |  | $ 9,735 |  |  |  |
Granted (in dollars per share) | $ / shares |  |  |  |  |  |  | $ 68.12 |  |  |  |
Incentive Plan |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |
Share-based payment award, number of shares authorized (in shares) |  |  |  |  |  |  | 8,850,000 |  |  | 1,700,000 | 1,000,000
Number of additional shares authorized (in shares) |  |  | 2,600,000 |  |  |  |  |  |  |  |
Share-based payment award, expiration period |  |  |  |  |  |  | 10 years |  |  |  |
Maximum percentage of exercise price at grant date fair value |  |  |  |  |  |  | 100.00% |  |  |  |
Share-based payment award, number of shares available for grant (in shares) |  |  |  |  |  |  | 1,895,135 |  |  |  |
Incentive Plan | Incentive Stock Options |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |
Share-based payment award, number of shares authorized (in shares) |  |  |  |  |  |  | 600,000 |  |  |  |
Subsequent Event |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |
Common stock, dividends declared (in dollars per share) | $ / shares | $ 0.22 |  |  |  |  |  |  |  |  |  |
Subsequent Event | Restricted Stock, Subject to Performance Conditions | Senior Executives |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of recipients of stock-based compensation award | executive | 4 |  |  |  |  |  |  |  |  |  |
Share-based payment award, award vesting period | 36 months |  |  |  |  |  |  |  |  |  |
Instruments grants in period (in shares) | 531,456 |  |  |  |  |  |  |  |  |  |
Post-vesting holding period | 2 years |  |  |  |  |  |  |  |  |  |
Target number of shares to be vested if performance condition is attained (in shares) | 177,152 |  |  |  |  |  |  |  |  |  |
Subsequent Event | Restricted Stock, Subject to Performance Conditions | Senior Executives | Minimum |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of shares to be vested if performance condition is attained (in shares) | 88,578 |  |  |  |  |  |  |  |  |  |
Subsequent Event | Restricted Stock, Subject to Performance Conditions | Senior Executives | Maximum |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of shares to be vested if performance condition is attained (in shares) | 531,456 |  |  |  |  |  |  |  |  |  |
Subsequent Event | Restricted Stock, Subject to Performance Conditions | Executives and Key Employees |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |
Share-based payment award, award vesting period | 36 months |  |  |  |  |  |  |  |  |  |
Subsequent Event | Restricted Stock and Restricted Stock Units |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |
Equity instruments other than options, granted in period, fair value | $ | $ 15,073 |  |  |  |  |  |  |  |  |  |
Granted (in dollars per share) | $ / shares | $ 85.09 |  |  |  |  |  |  |  |  |  |
Subsequent Event | Restricted Stock and Restricted Stock Units, Subject To Performance Conditions |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |
Instruments grants in period (in shares) | 147,141 |  |  |  |  |  |  |  |  |  |
Subsequent Event | Restricted Stock and Restricted Stock Units, Subject To Performance Conditions | Executive Officer and Key Employees |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |
Number of recipients of stock-based compensation award | executive | 29 |  |  |  |  |  |  |  |  |  |
Equity instruments other than options, granted in period, fair value | $ | $ 9,855 |  |  |  |  |  |  |  |  |  |
Granted (in dollars per share) | $ / shares | $ 66.86 |  |  |  |  |  |  |  |  |  |
O 2025 A Dividends |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |
Common stock, dividends declared (in dollars per share) | $ / shares |  |  |  |  |  |  | $ 0.72 |  |  |  |
O 2024 Dividends |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |
Common stock, dividends declared (in dollars per share) | $ / shares |  |  |  |  |  |  |  | $ 0.60 |  |  |
O 2023 Dividends |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |
Common stock, dividends declared (in dollars per share) | $ / shares |  |  |  |  |  |  |  |  | $ 0.45 |  |
S 2023 Dividends |  |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |  |
Common stock, dividends declared (in dollars per share) | $ / shares |  |  |  |  |  |  |  | $ 2.00 |  |  |

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