Consolidated Statements of Cash Flows - Unaudited (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Feb. 28, 2013	Feb. 29, 2012
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 94,307	$ 92,290
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	18,010	16,692
Stock-based compensation expense	26,373	11,925
Deferred income taxes	(2,394)	(91)
Gain on sale of assets	(2)	(1)
Tax benefits from share-based payment arrangements	(9,870)	(4,973)
Changes in assets and liabilities, net of effects of acquisition
Accounts receivable, net of reserves	(11,569)	3,545
Accounts payable and accrued expenses	5,038	155
Accrued compensation	(22,061)	(16,298)
Deferred fees	1,937	697
Taxes payable, net of prepaid taxes	(3,295)	(3,372)
Prepaid expenses and other assets	772	(456)
Deferred rent and other non-current liabilities	(282)	(922)
Other working capital accounts, net	74	(732)
Net cash provided by operating activities	97,038	98,459
CASH FLOWS FROM INVESTING ACTIVITIES
Acquisition of business, net of cash acquired	(705)	0
Purchases of investments	(8,098)	(15,000)
Proceeds from sales of investments	7,500	0
Purchases of property, equipment and leasehold improvements, net of proceeds from dispositions	(9,084)	(10,644)
Net cash used in investing activities	(10,387)	(25,644)
CASH FLOWS FROM FINANCING ACTIVITIES
Dividend payments	(27,280)	(24,182)
Repurchase of common stock	(139,010)	(59,795)
Proceeds from employee stock plans	31,306	13,843
Tax benefits from share-based payment arrangements	9,870	4,973
Net cash used in financing activities	(125,114)	(65,161)
Effect of exchange rate changes on cash and cash equivalents	733	(4,341)
Net (decrease) increase in cash and cash equivalents	(37,730)	3,313
Cash and cash equivalents at beginning of period	189,044	181,685
Cash and cash equivalents at end of period	$ 151,314	$ 184,998