Income Taxes - Components of Net Deferred Tax Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2022	Sep. 30, 2021
Deferred tax assets -
Valuation reserves and non-deductible expenses	$ 4,274	$ 4,939
Stock compensation expense not deductible	2,609	2,276
Net operating loss and tax credit carryforwards	12,108	12,711
Intangible asset basis differences and amortization	1,254	505
Unrepatriated earnings	1,205	0
Other	1,357	1,512
Subtotal	22,807	21,943
Less valuation allowance	(1,427)	(1,624)
Deferred tax assets	21,380	20,319
Deferred tax liabilities -
Property, plant and equipment basis differences and depreciation	(5,540)	(4,778)
Intangible asset basis differences and amortization	(6,218)	(7,000)
Unrepatriated earnings	(922)	(865)
Deferred tax liabilities	(12,680)	(12,643)
Net deferred tax assets	$ 8,700	$ 7,676