Income Taxes - Schedule of Provision For (Benefit From) Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Federal	$ 2,187	$ 13,130	$ 3,009
State	1,266	(945)	2,003
Foreign	25,199	33,867	28,213
Current provision for income taxes	28,652	46,052	33,225
Federal	(26,811)	22,911	(12,594)
State	(4,063)	1,759	(445)
Foreign	6,233	(22,962)	(43,517)
Deferred provision for (benefit from) income taxes	(24,641)	1,708	(56,556)
Total provision (benefit) for income taxes	$ 4,011	$ 47,760	$ (23,331)