CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Mar. 31, 2022	Mar. 31, 2021
Statement Of Income And Comprehensive Income [Abstract]
Net (loss) income	$ (476)	$ 11,163	$ 18,568	$ 32,104
Other comprehensive (loss) income:
Foreign currency translation adjustments	(5,295)	(12,321)	(10,684)	1,849
Pension adjustments, net	61	104	134	74
Net unrealized loss on available-for-sale securities	(132)		(167)
Total other comprehensive (loss) income	(5,366)	(12,217)	(10,717)	1,923
Comprehensive (loss) income	$ (5,842)	$ (1,054)	$ 7,851	$ 34,027