Fair Value Measurements (Tables)

6 Months Ended

Mar. 31, 2023

Fair Value Disclosures [Abstract]

Assets and Liabilities Measured at Fair Value on Recurring Basis

			Fair Value Measurements at Reporting Date Using
			Quoted Prices in				Significant
			Active Markets for		Significant Other		Unobservable
	March 31,		Identical Assets		Observable Inputs		Inputs
Description	2023		(Level 1)		(Level 2)		(Level 3)
Assets:
Cash equivalents	$	510,643	$	499,283	$	11,360	$	—
Available-for-sale securities		779,827		208,527		571,300		—
Foreign exchange contracts		150		—		150		—
Net investment hedge		1,278		—		1,278		—
Total assets	$	1,291,898	$	707,810	$	584,088	$	—
Liabilities:
Contingent consideration liability	$	1,406	$	—	$	—	$	1,406
Foreign exchange contracts		164		—		164		—
Total liabilities	$	1,570	$	—	$	164	$	1,406

			Fair Value Measurements at Reporting Date Using
			Quoted Prices in				Significant
			Active Markets for		Significant Other		Unobservable
	September 30,		Identical Assets		Observable Inputs		Inputs
Description	2022		(Level 1)		(Level 2)		(Level 3)
Assets:
Cash equivalents	$	374,804	$	374,055	$	749	$	—
Available-for-sale securities		1,263,782		651,800		611,982		—
Foreign exchange contracts		634		—		634		—
Net investment hedge		124,789		—		124,789		—
Total assets	$	1,764,009	$	1,025,855	$	738,154	$	—
Liabilities:
Foreign exchange contracts	$	230	$	—	$	230	$	—
Total liabilities	$	230	$	—	$	230	$	—