Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Aug. 31, 2013	Aug. 31, 2012	Aug. 31, 2011
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 198,637	$ 188,809	$ 171,046
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	35,779	33,779	36,847
Stock-based compensation expense	39,951	21,982	25,773
Deferred income taxes	3,175	(3,760)	(1,806)
Gain on sale of assets	(26)		(22)
Tax benefits from share-based payment arrangements	(25,225)	(11,159)	(18,331)
Changes in assets and liabilities, net of effects of acquisition
Accounts receivable, net of reserves	859	2,083	(15,311)
Accounts payable and accrued expenses	3,355	9	715
Accrued compensation	(776)	519	(7,882)
Deferred fees	(1,107)	(2,573)	3,219
Taxes payable, net of prepaid taxes	13,498	4,209	20,387
Prepaid expenses and other assets	2,105	(445)	(6,579)
Deferred rent and other non-current liabilities	(2,846)	(905)	(483)
Other working capital accounts, net	2,430	(583)	(437)
Net cash provided by operating activities	269,809	231,965	207,136
CASH FLOWS FROM INVESTING ACTIVITIES
Acquisition of business, net of cash acquired	(705)	(21,329)
Purchases of investments	(15,613)	(15,000)
Proceeds from sales of investments	14,423
Purchases of property, equipment and leasehold improvements, net of proceeds from dispositions	(18,517)	(22,520)	(29,343)
Net cash used in investing activities	(20,412)	(58,849)	(29,343)
CASH FLOWS FROM FINANCING ACTIVITIES
Dividend payments	(56,002)	(49,983)	(43,949)
Repurchase of common stock	(332,168)	(153,641)	(216,584)
Proceeds from employee stock plans	124,537	33,747	43,079
Tax benefits from share-based payment arrangements	25,225	11,159	18,331
Net cash used in financing activities	(238,408)	(158,718)	(199,123)
Effect of exchange rate changes on cash and cash equivalents	(3,406)	(7,039)	7,274
Net increase (decrease) in cash and cash equivalents	7,583	7,359	(14,056)
Cash and cash equivalents at beginning of year	189,044	181,685	195,741
Cash and cash equivalents at end of year	196,627	189,044	181,685
Cash paid during the year for income taxes, net of refunds	45,732	73,219	36,869
Dividends declared, not paid	15,164	13,727	12,165
Stock issued for acquisition of business		$ 3,974