CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE (LOSS) INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 11,163	$ 12,812	$ 32,104	$ 1,529
Other comprehensive (loss) income:
Foreign currency translation adjustments	(12,321)	(7,284)	1,849	(2,380)
Pension adjustments, net	104	90	74	1,016
Total other comprehensive (loss) income	(12,217)	(7,194)	1,923	(1,364)
Comprehensive (loss) income	$ (1,054)	$ 5,618	$ 34,027	$ 165