CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Cash flows from operating activities:
Net income	$ 282,842	$ 306,364
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	15,819	20,066
Share-based compensation	86,363	84,099
Deferred income taxes	1,825	(11,064)
Net (gain) loss on marketable securities	7,985	(4,706)
Non-cash operating lease costs	12,094	12,056
Provision for doubtful accounts	975	551
Net loss on sales and abandonment of property and equipment	210	107
Gains on product line asset sales and business divestiture	0	(100,139)
Changes in operating assets and liabilities:
Accounts receivable	12,134	56,655
Prepaid expenses and other assets	4,945	5,172
Accounts payable	(2,978)	(4,165)
Accrued compensation and employee benefits	(22,355)	(24,990)
Other liabilities	(33,166)	(5,388)
Deferred revenue	(2,069)	(2,556)
Net cash provided by operating activities	364,624	332,062
Cash flows from investing activities:
Purchases of property and equipment	(5,232)	(5,792)
Proceeds from sales of marketable securities	6,575	2,294
Purchases of marketable securities	(8,022)	(5,121)
Proceeds from product line asset sales and business divestiture	2,257	146,428
Purchase of equity investment	0	(210)
Net cash provided by (used in) investing activities	(4,422)	137,599
Cash flows from financing activities:
Proceeds from revolving line of credit and term loan	1,010,000	429,000
Payments on revolving line of credit and term loan	(855,500)	(208,000)
Proceeds from issuance of senior notes	550,000	0
Payments on debt issuance costs	(8,819)	0
Payments on finance leases	0	(177)
Proceeds from issuance of treasury stock under employee stock plans	11,117	14,580
Taxes paid related to net share settlement of equity awards	(49,027)	(88,770)
Repurchases of common stock	(1,048,027)	(541,205)
Net cash used in financing activities	(390,256)	(394,572)
Effect of exchange rate changes on cash	(10,238)	5,129
Increase (decrease) in cash and cash equivalents	(40,292)	80,218
Cash and cash equivalents, beginning of period	195,354	157,394
Cash and cash equivalents, end of period	155,062	237,612
Supplemental disclosures of cash flow information:
Cash paid for income taxes, net of refunds of $1,021 and $289 during the nine-month periods ended June 30, 2022 and 2021, respectively	45,984	34,465
Cash paid for interest	52,058	36,764
Supplemental disclosures of non-cash investing and financing activities:
Purchase of property and equipment included in accounts payable	$ 11	$ 564