CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Class A Common Stock	Class B Common Stock	Common Stock Class A Common Stock	Common Stock Class B Common Stock	Additional Paid-in Capital	Retained Earnings	Non-controlling Interest	Accumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Sep. 30, 2023				14,420,000	1,430,000
Beginning balance at Sep. 30, 2023	$ 414,078			$ 144	$ 14	$ 193,018	$ 165,432	$ 55,469	$ 1
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(7,970)						(7,170)	(800)
Shares issued upon vesting of equity-based awards, net of tax withholding (in shares)				124,000
Distributions to members	(3,789)						0	(3,789)
Purchase of non-controlling interest	(18,840)					716		(19,556)
Shares issued upon vesting of equity-based awards, net of tax withholding	(1,552)			$ 1		(1,553)
Equity-based compensation	2,392					2,392
Currency translation adjustment	(9)							(1)	(8)
Ending balance (in shares) at Dec. 31, 2023				14,544,000	1,430,000
Ending balance at Dec. 31, 2023	384,310			$ 145	$ 14	194,573	158,262	31,323	(7)
Beginning balance (in shares) at Sep. 30, 2024		14,686,696	1,429,940	14,687,000	1,430,000
Beginning balance at Sep. 30, 2024	390,753			$ 147	$ 14	202,921	159,625	29,943	(1,897)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net loss	(13,612)						(11,971)	(1,641)
Shares issued upon vesting of equity-based awards, net of tax withholding (in shares)				160,000
Shares issued upon vesting of equity-based awards, net of tax withholding	(1,823)			$ 1		(1,824)
Equity-based compensation	2,170					2,170
Currency translation adjustment	20							2	18
Change in fair value of interest rate swaps, net of reclassification adjustment and tax expense	6,110							537	5,573
Ending balance (in shares) at Dec. 31, 2024		14,847,008	1,429,940	14,847,000	1,430,000
Ending balance at Dec. 31, 2024	$ 383,618			$ 148	$ 14	$ 203,267	$ 147,654	$ 28,841	$ 3,694