CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Paid-in Capital	Retained Earnings
Beginning balance (in shares) at Sep. 30, 2023		31,351
Beginning balance at Sep. 30, 2023	$ 1,102,819	$ 31	$ 864,778	$ 238,010
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss) and comprehensive income (loss)	88,109			88,109
Stock-based compensation expense	5,536		5,536
Stock option exercises (in shares)		2
Stock option exercises	16		16
Shares issued under employee stock plans, net (in shares)		383
Shares issued under employee stock plans, net	1	$ 1
Forfeiture and other settlements of restricted stock (in shares)		(26)
Common stock redeemed for tax liability (in shares)		(173)
Common stock redeemed for tax liability	$ (5,237)		(5,237)
Share repurchases (in shares)	(455)	(455)
Share repurchases	$ (12,929)	$ (1)	(12,928)
Ending balance (in shares) at Jun. 30, 2024		31,082
Ending balance at Jun. 30, 2024	1,178,315	$ 31	852,165	326,119
Beginning balance (in shares) at Mar. 31, 2024		31,547
Beginning balance at Mar. 31, 2024	1,161,577	$ 32	862,636	298,909
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss) and comprehensive income (loss)	27,210			27,210
Stock-based compensation expense	2,474		2,474
Shares issued under employee stock plans, net (in shares)		7
Forfeiture and other settlements of restricted stock (in shares)		(16)
Common stock redeemed for tax liability (in shares)		(1)
Common stock redeemed for tax liability	$ (17)		(17)
Share repurchases (in shares)	(455)	(455)
Share repurchases	$ (12,929)	$ (1)	(12,928)
Ending balance (in shares) at Jun. 30, 2024		31,082
Ending balance at Jun. 30, 2024	1,178,315	$ 31	852,165	326,119
Beginning balance (in shares) at Sep. 30, 2024		31,048
Beginning balance at Sep. 30, 2024	1,232,111	$ 31	853,895	378,185
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss) and comprehensive income (loss)	15,584			15,584
Stock-based compensation expense	5,442		5,442
Stock option exercises (in shares)		11
Stock option exercises	107		107
Shares issued under employee stock plans, net (in shares)		286
Forfeiture and other settlements of restricted stock (in shares)		(32)
Common stock redeemed for tax liability (in shares)		(96)
Common stock redeemed for tax liability	$ (3,136)		(3,136)
Share repurchases (in shares)	(1,500)	(1,491)
Share repurchases	$ (33,077)	$ (1)	(33,076)
Ending balance (in shares) at Jun. 30, 2025		29,726
Ending balance at Jun. 30, 2025	1,217,031	$ 30	823,232	393,769
Beginning balance (in shares) at Mar. 31, 2025		30,303
Beginning balance at Mar. 31, 2025	1,228,067	$ 30	833,944	394,093
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss) and comprehensive income (loss)	(324)			(324)
Stock-based compensation expense	1,817		1,817
Stock option exercises	1		1
Shares issued under employee stock plans, net (in shares)		12
Forfeiture and other settlements of restricted stock (in shares)		(2)
Common stock redeemed for tax liability (in shares)		(1)
Common stock redeemed for tax liability	$ (15)		(15)
Share repurchases (in shares)	(586)	(586)
Share repurchases	$ (12,515)		(12,515)
Ending balance (in shares) at Jun. 30, 2025		29,726
Ending balance at Jun. 30, 2025	$ 1,217,031	$ 30	$ 823,232	$ 393,769