Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Cash flows from operating activities:
Net income (loss)	$ (27,460)	$ 51,987	$ 6,239
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Stock-based compensation	86,400	82,939	76,708
Depreciation and amortization	77,824	87,408	86,742
Provision (benefit) from deferred income taxes	1,708	(56,556)	(28,289)
Other non-cash costs, net	(4,148)	534	2,272
Changes in operating assets and liabilities, excluding the effects of acquisitions:
Accounts receivable	29,446	20,396	12,832
Accounts payable and accrued expenses	16,200	5,251	20,315
Accrued compensation and benefits	(12,098)	(6,988)	(34,846)
Deferred revenue	45,875	56,141	5,808
Accrued income taxes, net of income tax receivable	232	10,323	(798)
Other current assets and prepaid expenses	(2,829)	(10,642)	690
Other noncurrent assets and liabilities	73,995	6,959	(12,470)
Net cash provided by operating activities	285,145	247,752	135,203
Cash flows from investing activities:
Additions to property and equipment	(64,411)	(36,041)	(25,444)
Purchases of short- and long-term marketable securities	(33,027)	(24,311)	(19,726)
Proceeds from maturities of short- and long-term marketable securities	31,976	18,140	18,785
Acquisitions of businesses, net of cash acquired	(86,737)	(3,000)	(4,960)
Purchases of investments	(7,500)	(1,000)	0
Settlement of net investment hedges	9,675	0	0
Proceeds from sales of investments	0	0	15,218
Purchase of intangible asset	0	(3,000)	0
Net cash used by investing activities	(150,024)	(49,212)	(16,127)
Cash flows from financing activities:
Borrowings under credit facility	205,000	250,000	150,000
Repayments of borrowings under credit facility	(180,000)	(320,000)	(190,000)
Repurchases of common stock	(114,994)	(1,100,000)	(50,991)
Proceeds from issuance of common stock	12,975	1,015,654	10,778
Payments of withholding taxes in connection with vesting of stock-based awards	(44,366)	(45,374)	(26,654)
Credit facility origination costs	0	(2,851)	(184)
Contingent consideration	(1,575)	(8,275)	(11,054)
Net cash used by financing activities	(122,960)	(210,846)	(118,105)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	(2,565)	(7,810)	1,066
Net increase (decrease) in cash, cash equivalents and restricted cash	9,596	(20,116)	2,037
Cash, cash equivalents and restricted cash, beginning of year	261,093	281,209	279,172
Cash, cash equivalents and restricted cash, end of year	270,689	261,093	281,209
Supplemental disclosure of non-cash financing activities:
Fair value of contingent consideration recorded for acquisition	$ 0	$ 2,100	$ 0