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STOCKHOLDERS' EQUITY AND EQUITY COMPENSATION - Summary of stock-based compensation expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Stockholders' Equity Note [Abstract]
Restricted stock	$ 25,483	$ 18,305	$ 20,529
ESOP	0	8,533	20,583
Total stock-based compensation	$ 25,483	$ 26,838	41,112
Special dividend ESOP charges			$ 15,494

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Special Dividend ESOP Charges

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- Definition

Amount, after tax, of expense for award under share-based payment arrangement.

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The amount of plan compensation cost recognized during the period.

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Amount of noncash expense for award of restricted stock or unit under share-based payment arrangement.

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