CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 19,044	$ 20,941
Other comprehensive (loss) income:
Foreign currency translation adjustments	(5,389)	14,170
Pension adjustments, net	73	(30)
Net unrealized loss on available-for-sale securities	(35)
Total other comprehensive (loss) income	(5,351)	14,140
Comprehensive income	$ 13,693	$ 35,081