Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2019
Cash flows from operating activities:
Net income (loss)	$ 476,923	$ 130,695	$ (27,460)
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	85,239	80,817	77,824
Amortization of right-of-use lease assets	37,295	38,687	0
Stock-based compensation	177,289	115,149	86,400
Gain on investment	(68,829)	0	0
Other non-cash items, net	(1,381)	(3,167)	(4,148)
Provision (benefit) from deferred income taxes	(158,105)	(24,641)	1,708
Accounts receivable	(119,418)	(32,365)	29,446
Accounts payable and accrued expenses	25,096	(5,135)	16,200
Accrued compensation and benefits	16,775	10,282	(12,098)
Deferred revenue	58,702	17,046	45,875
Income taxes	13,979	(26,616)	232
Other current assets and prepaid expenses	(14,206)	36,189	(2,829)
Operating lease liabilities	(7,129)	(11,110)	0
Other noncurrent assets and liabilities	(153,421)	(92,023)	73,995
Net cash provided by operating activities	368,809	233,808	285,145
Cash flows from investing activities:
Additions to property and equipment	(24,713)	(20,196)	(64,411)
Purchases of short- and long-term marketable securities	(7,562)	(33,869)	(33,027)
Proceeds from sales of short- and long-term marketable securities	56,170	1,521	1,507
Proceeds from maturities of short- and long-term marketable securities	9,861	30,521	30,469
Acquisitions of businesses, net of cash acquired	(718,030)	(483,478)	(86,737)
Purchases of investments	(4,000)	0	(7,500)
Purchase of intangible assets	(550)	(11,050)	0
Settlement of net investment hedges	965	(9,421)	9,675
Net cash used in investing activities	(687,859)	(525,972)	(150,024)
Cash flows from financing activities:
Proceeds from issuance of Senior Notes	0	1,000,000	0
Borrowings under credit facility	600,000	455,000	205,000
Repayments of Senior Notes	0	(500,000)	0
Repayments of borrowings under credit facility	(168,000)	(610,125)	(180,000)
Repurchases of common stock	(30,000)	0	(114,994)
Proceeds from issuance of common stock	21,575	18,382	12,975
Debt issuance costs	0	(17,107)	0
Contingent consideration	0	0	(1,575)
Debt early redemption premium	0	(15,000)	0
Payments of withholding taxes in connection with stock-based awards	(52,957)	(33,740)	(44,366)
Payments of principal for financing leases	(354)	0	0
Net cash provided by (used in) financing activities	370,264	297,410	(122,960)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(127)	25	(2,565)
Net change in cash, cash equivalents, and restricted cash	51,087	5,271	9,596
Cash, cash equivalents, and restricted cash, beginning of period	275,960	270,689	261,093
Cash, cash equivalents, and restricted cash, end of period	327,047	275,960	270,689
Supplemental disclosure of non-cash financing activities:
Withholding taxes in connection with stock-based awards, accrued	$ 120	$ 0	$ 0