Income Taxes - Provision (Benefit) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Income Tax Expense (Benefit), Continuing Operations [Abstract]
Income tax expense (benefit)	$ (1,207)	$ 7,293	$ (9,107)	$ (560)
Deferred tax benefit resulting from the extension of a tax incentive in China			1,400
Benefit related to stock compensation windfalls				4,600
Charge to increase the deferred tax liability to reflect a change in the blended state income tax rate that results from the sale of the semiconductor business assets				$ 700
Pre-tax income not subject to income taxes	$ 18,500		$ 18,500