Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2013
Cash flows from operating activities:
Net income	$ 47,557	$ 160,194	$ 143,769
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Stock-based compensation	50,182	50,889	48,787
Depreciation and amortization	84,433	77,307	76,551
Benefit from deferred income taxes	(49,361)	(19,946)	(39,714)
Excess tax benefits realized from stock-based awards	(24)	(10,428)	(334)
Pension settlement loss	66,332	0	0
Other non-cash costs, net	157	(760)	339
Changes in operating assets and liabilities, excluding the effects of acquisitions:
Accounts receivable	29,723	7,554	17,308
Accounts payable and accrued expenses	31,134	(436)	(4,828)
Accrued compensation and benefits	(56,950)	8,974	11,036
Deferred revenue	8,852	24,998	6,727
Accrued income taxes, net of income tax receivable	(3,536)	19,134	(15,211)
Other current assets and prepaid expenses	(10,716)	4,417	(9,113)
Other noncurrent assets	(17,880)	(17,345)	(10,634)
Net cash provided by operating activities	179,903	304,552	224,683
Cash flows from investing activities:
Additions to property and equipment	(30,628)	(25,275)	(29,328)
Acquisitions of businesses, net of cash acquired	(98,411)	(323,525)	(245,843)
Purchases of investments	(11,000)	0	0
Other	0	0	721
Net cash used by investing activities	(140,039)	(348,800)	(274,450)
Cash flows from financing activities:
Borrowings under credit facility	185,000	1,386,250	0
Repayments of borrowings under revolving credit facility	(128,750)	(1,032,500)	(111,875)
Repurchases of common stock	(64,940)	(224,915)	(74,871)
Proceeds from issuance of common stock	41	877	4,884
Excess tax benefits realized from stock-based awards	24	10,428	334
Payments of withholding taxes in connection with vesting of stock-based awards	(29,207)	(26,857)	(14,996)
Credit facility origination costs	0	(7,930)	0
Payments to Business Combination Contingent Consideration Financing Activities	4,323	0	0
Net cash provided (used) by financing activities	(42,155)	105,353	(196,524)
Effect of exchange rate changes on cash and cash equivalents	(17,946)	(9,364)	(1,339)
Net increase (decrease) in cash and cash equivalents	(20,237)	51,741	(247,630)
Cash and cash equivalents, beginning of year	293,654	241,913	489,543
Cash and cash equivalents, end of year	273,417	293,654	241,913
Fair value of contingent consideration recorded for acquisition	$ 3,800	$ 13,048	$ 0