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 and comprehensive income	21,728			21,728
Stock-based compensation expense	1,673		1,673
Shares issued under employee stock plans, net (in shares)		362
Shares issued under employee stock plans, net	1	$ 1
Forfeiture and other settlements of restricted stock (in shares)		(8)
Common stock redeemed for tax liability (in shares)		(172)
Common stock redeemed for tax liability	(5,210)		(5,210)
Ending balance (in shares) at Dec. 31, 2023		31,533
Ending balance at Dec. 31, 2023	1,121,011	$ 32	861,241	259,738
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 and comprehensive income	3,130			3,130
Stock-based compensation expense	1,913		1,913
Shares issued under employee stock plans, net (in shares)		267
Forfeiture and other settlements of restricted stock (in shares)		(19)
Common stock redeemed for tax liability (in shares)		(94)
Common stock redeemed for tax liability	(3,106)		(3,106)
Ending balance (in shares) at Dec. 31, 2024		31,202
Ending balance at Dec. 31, 2024	$ 1,234,048	$ 31	$ 852,702	$ 381,315