Fair Value Measurements - Schedule of Financial Assets and Liabilities Measured at Fair Value (Details) - USD ($) $ in Thousands		Dec. 31, 2021	Sep. 30, 2021
Financial assets:
Cash equivalents	[1]	$ 107,320	$ 114,375
Convertible note		2,000	2,000
Equity securities		87,306	77,500
Forward contracts		1,486	5,363
Financial assets, fair value		200,133	199,238
Options		2,021
Financial liabilities:
Stock buyback pending settlement		5,260
Forward contracts		3,732	3,318
Financial liabilities, fair value		8,992	3,318
Level 1
Financial assets:
Cash equivalents	[1]	107,320	114,375
Convertible note		0	0
Equity securities		0	0
Forward contracts		0	0
Financial assets, fair value		107,320	114,375
Options		0
Financial liabilities:
Stock buyback pending settlement		5,260
Forward contracts		0	0
Financial liabilities, fair value		5,260	0
Level 2
Financial assets:
Cash equivalents	[1]	0	0
Convertible note		0	0
Equity securities		0	0
Forward contracts		1,486	5,363
Financial assets, fair value		3,507	5,363
Options		2,021
Financial liabilities:
Stock buyback pending settlement		0
Forward contracts		3,732	3,318
Financial liabilities, fair value		3,732	3,318
Level 3
Financial assets:
Cash equivalents	[1]	0	0
Convertible note		2,000	2,000
Equity securities		87,306	77,500
Forward contracts		0	0
Financial assets, fair value		89,306	79,500
Options		0
Financial liabilities:
Stock buyback pending settlement		0
Forward contracts		0	0
Financial liabilities, fair value		$ 0	$ 0

[1] Money market funds and time deposits.