CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Paid-in Capital	Retained Earnings
Beginning balance (in shares) at Sep. 30, 2022		30,880,000
Beginning balance at Sep. 30, 2022	$ 939,286	$ 31	$ 859,856	$ 79,399
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income and comprehensive income	158,611			158,611
Stock-based compensation expense	7,275		7,275
Stock option exercises (in shares)		14,000
Stock option exercises	262		262
Shares issued under employee stock plans, net (in shares)		675,000
Shares issued under employee stock plans, net	0
Forfeiture and other settlements of restricted stock (in shares)		(12,000)
Forfeiture and other settlements of restricted stock	0
Common stock redeemed for tax liability (in shares)		(206,000)
Common stock redeemed for tax liability	$ (2,615)		(2,615)
Share repurchases (in shares)	0
Ending balance (in shares) at Sep. 30, 2023		31,351,000
Ending balance at Sep. 30, 2023	$ 1,102,819	$ 31	864,778	238,010
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income and comprehensive income	140,175			140,175
Stock-based compensation expense	7,391		7,391
Stock option exercises (in shares)		3,000
Stock option exercises	20		20
Shares issued under employee stock plans, net (in shares)		387,000
Shares issued under employee stock plans, net	1	$ 1
Forfeiture and other settlements of restricted stock (in shares)		(61,000)
Forfeiture and other settlements of restricted stock	0
Common stock redeemed for tax liability (in shares)		(177,000)
Common stock redeemed for tax liability	$ (5,366)		(5,366)
Share repurchases (in shares)	(455,000)	(455,000)
Share repurchases	$ (12,929)	$ (1)	(12,928)
Ending balance (in shares) at Sep. 30, 2024		31,048,000
Ending balance at Sep. 30, 2024	1,232,111	$ 31	853,895	378,185
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income and comprehensive income	45,588			45,588
Stock-based compensation expense	7,338		7,338
Stock option exercises (in shares)		11,000
Stock option exercises	107		107
Shares issued under employee stock plans, net (in shares)		327,000
Shares issued under employee stock plans, net	0
Forfeiture and other settlements of restricted stock (in shares)		(36,000)
Forfeiture and other settlements of restricted stock	0
Common stock redeemed for tax liability (in shares)		(97,000)
Common stock redeemed for tax liability	$ (3,161)		(3,161)
Share repurchases (in shares)	(1,500,000)	(1,491,000)
Share repurchases	$ (33,077)	$ (1)	(33,076)
Ending balance (in shares) at Sep. 30, 2025		29,762,000
Ending balance at Sep. 30, 2025	$ 1,248,906	$ 30	$ 825,103	$ 423,773