CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2011
Cash flows from operating activities:
Net income	$ 90,095	$ 92,004	$ 71,562
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	33,214	21,549	24,197
Share-based compensation	25,850	21,229	15,500
Deferred income taxes	3,671	(7,121)	1,252
Tax effect from share-based payment arrangements	2,887	6,079	(2,599)
Excess tax benefits from share-based payment arrangements	(6,362)	(8,079)	(1,664)
Net amortization of premium on marketable securities	8	221	554
Provision of (benefit from) doubtful accounts	327	(122)	(583)
Net loss on sales of property and equipment	351	63	169
Changes in operating assets and liabilities:
Accounts receivable	1,286	(26,490)	8,571
Prepaid expenses and other assets	(822)	802	2,060
Accounts payable	(590)	6,810	(1,749)
Accrued compensation and employee benefits	(11,729)	11,314	3,154
Other liabilities	1,823	1,455	18,727
Deferred revenue	(3,889)	10,032	(2,995)
Net cash provided by operating activities	136,120	129,746	136,156
Cash flows from investing activities:
Purchases of property and equipment	(24,147)	(25,483)	(14,020)
Purchases of marketable securities		(48,067)	(144,224)
Proceeds from sale of marketable securities			13,644
Proceeds from maturities of marketable securities	22,000	131,659	92,759
Cash paid for acquisitions, net of cash acquired	(32,874)	(123,631)
Distribution from (purchase of) cost method investees	50	(148)	140
Net cash used in investing activities	(34,971)	(65,670)	(51,701)
Cash flows from financing activities:
Proceeds from revolving line of credit	30,000
Payments on revolving line of credit and other short-term loans	(18,676)	(5,466)
Payments on senior notes	(49,000)	(8,000)	(8,000)
Debt issuance costs			(736)
Proceeds from issuance of treasury stock under employee stock plans	30,256	70,793	7,613
Dividends paid	(2,824)	(2,803)	(3,140)
Repurchases of common stock	(82,752)	(191,056)	(91,422)
Excess tax benefits from share-based payment arrangements	6,362	8,079	1,664
Net cash used in financing activities	(86,634)	(128,453)	(94,021)
Effect of exchange rate changes on cash	(2,946)	234	(881)
Increase (decrease) in cash and cash equivalents	11,569	(64,143)	(10,447)
Cash and cash equivalents, beginning of year	71,609	135,752	146,199
Cash and cash equivalents, end of year	83,178	71,609	135,752
Supplemental disclosures of cash flow information:
Cash paid for income taxes, net of refunds of $2,471, $584 and $207 during the years ended September 30, 2013, 2012 and 2011, respectively	24,141	36,852	11,460
Cash paid for interest	31,011	31,421	31,974
Supplemental disclosures of non-cash investing and financing activities:
Unsettled repurchases of common stock	2,141		6,765
Purchase of property and equipment included in accounts payable	$ 681	$ 641	$ 4,790