EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
Numerator:
Net (loss) income	$ (15,175)	$ 472,872	$ 689,899
Less: Undistributed earnings allocated to participating securities	0	6,135	10,637
Net income available to common shareholders, basic	(15,175)	466,737	679,262
Net income available to common shareholders, diluted	$ (15,175)	$ 466,737	$ 679,262
Denominator:
Basic weighted average common shares (in shares)	34,035,000	36,390,000	38,797,000
Effect of dilutive securities: Non-participating employee stock options (in shares)	0	399,000	531,000
Diluted weighted average common shares outstanding (in shares)	34,035,000	36,789,000	39,328,000
Basic earnings per share (in dollars per share)	$ (0.45)	$ 12.83	$ 17.51
Diluted earnings per share (in dollars per share)	$ (0.45)	$ 12.69	$ 17.27
Common Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of earnings per share, amount (in shares)	0	0	0