CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 13,057	$ 14,415
Other comprehensive income, net of tax:
Foreign currency translation adjustments	9,645	1,677
Unrealized gains (losses) on marketable securities, net of tax effects of $0 and ($38) during the three months ended December 31, 2019 and 2018	10	(121)
Actuarial losses, net of tax effects of $1 and $2 during the three months ended December 31, 2019 and 2018	(12)	(9)
Total other comprehensive income, net of tax	9,643	1,547
Comprehensive income	$ 22,700	$ 15,962