INCOME TAXES - Schedule of Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2022
Deferred tax asset:
State loss carryforwards and other benefits	$ 15,555	$ 15,744
Inventory reserves	14,968	12,191
Warranty reserves	4,716	4,148
Accrued expenses	13,717	11,996
Stock-based compensation	14,403	13,502
Lease liabilities	28,531	24,063
Unrealized loss in other comprehensive income	555	0
Valuation allowance	(2,314)	(5,557)	$ (4,960)
Total deferred tax assets	90,131	76,087
Deferred tax liabilities:
Intangible assets — net	32,949	37,272
Property, plant and equipment	68,120	75,778
Right-of-use assets	25,644	21,728
Unrealized gain in other comprehensive income	0	615
Indemnification receivable related to warranty reserves	300	203
Total deferred tax liabilities	127,013	135,596
Net deferred tax liability	$ 36,882	$ 59,509