CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 26,028	$ 13,057
Other comprehensive income, net of tax:
Foreign currency translation adjustments	13,264	9,645
Unrealized gains on marketable securities, net of tax effects of $0 and $0 during the three months ended December 31, 2020 and 2019		10
Actuarial losses, net of tax effects of $5 and $1 during the three months ended December 31, 2020 and 2019	(38)	(12)
Total other comprehensive income, net of tax	13,226	9,643
Comprehensive income	$ 39,254	$ 22,700