Income Taxes - Provision (Benefit) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022
Income Tax Expense (Benefit), Continuing Operations [Abstract]
Income tax expense (benefit)	$ (3,260)	$ (3,173)	$ (7,900)	$ (7,853)
Deferred tax benefit resulting from the extension of a tax incentive in China			1,400
Benefit related to stock compensation windfalls				4,500
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				600
Pre-tax income not subject to income taxes	$ 17,100		$ 17,100
Pre-tax gains (losses)		$ (1,800)		$ (5,000)