CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Cash flows from operating activities:
Net income	$ 327,951	$ 282,842
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	11,642	15,819
Share-based compensation	89,750	86,363
Deferred income taxes	(37,795)	1,825
Net (gain) loss on marketable securities	(3,854)	7,985
Non-cash operating lease costs	11,215	12,094
Provision for doubtful accounts	1,106	975
Gain (Loss) on Disposition of Assets	1,941	0
Net loss on sales and abandonment of property and equipment	555	210
Changes in operating assets and liabilities:
Accounts receivable	(65,005)	12,134
Prepaid expenses and other assets	(1,487)	4,945
Accounts payable	(62)	(2,978)
Accrued compensation and employee benefits	(14,931)	(22,355)
Other liabilities	(20,242)	(33,166)
Deferred revenue	7,964	(2,069)
Net cash provided by operating activities	304,866	364,624
Cash flows from investing activities:
Purchases of property and equipment	(3,169)	(5,232)
Proceeds from sales of marketable securities	4,969	6,575
Purchases of marketable securities	(8,648)	(8,022)
Proceeds from product line asset sales, net of cash transferred	(6,126)	2,257
Net cash used in investing activities	(12,974)	(4,422)
Cash flows from financing activities:
Proceeds from revolving line of credit and term loan	339,000	1,010,000
Payments on revolving line of credit and term loan	(265,250)	(855,500)
Proceeds from issuance of senior notes	0	550,000
Payments on debt issuance costs	0	(8,819)
Proceeds from issuance of treasury stock under employee stock plans	15,615	11,117
Taxes paid related to net share settlement of equity awards	(75,443)	(49,027)
Repurchases of common stock	(285,158)	(1,048,027)
Net cash used in financing activities	(271,236)	(390,256)
Effect of exchange rate changes on cash	9,164	(10,238)
Increase (decrease) in cash and cash equivalents	29,820	(40,292)
Cash and cash equivalents, beginning of period	133,202	195,354
Cash and cash equivalents, end of period	163,022	155,062
Supplemental disclosures of cash flow information:
Cash paid for income taxes, net of refunds of $567 and $1,021 during the nine-month periods ended June 30, 2023 and 2022, respectively	107,081	45,984
Cash paid for interest	86,122	52,058
Supplemental disclosures of non-cash investing and financing activities:
Purchase of property and equipment included in accounts payable	53	11
Unsettled repurchases of common stock	$ 4,748	$ 0