Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Aug. 31, 2012	Aug. 31, 2011	Aug. 31, 2010
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 188,809	$ 171,046	$ 150,211
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	33,779	36,847	37,343
Stock-based compensation expense	21,982	25,773	14,065
Deferred income taxes	(3,760)	(1,806)	(5,827)
Gain on sale of assets		(22)	(80)
Tax benefits from share-based payment arrangements	(11,159)	(18,331)	(24,492)
Accounts receivable, net of reserves	2,083	(15,311)	3,883
Accounts payable and accrued expenses	9	715	(1,308)
Accrued compensation	519	(7,882)	7,440
Deferred fees	(2,573)	3,219	(7,759)
Taxes payable, net of prepaid taxes	4,209	20,387	35,781
Prepaid expenses and other assets	(445)	(6,579)	281
Deferred rent and other non-current liabilities	(905)	(483)	(359)
Other working capital accounts, net	(583)	(437)	1,901
Net cash provided by operating activities	231,965	207,136	211,080
CASH FLOWS FROM INVESTING ACTIVITIES
Acquisition of businesses, net of cash acquired	(21,329)		(55,180)
Purchases of investments	(15,000)
Purchases of property, equipment and leasehold improvements, net of proceeds from dispositions	(22,520)	(29,343)	(20,768)
Net cash used in investing activities	(58,849)	(29,343)	(75,948)
CASH FLOWS FROM FINANCING ACTIVITIES
Dividend payments	(49,983)	(43,949)	(38,494)
Repurchase of common stock	(153,641)	(216,584)	(192,816)
Proceeds from employee stock plans	33,747	43,079	55,250
Tax benefits from share-based payment arrangements	11,159	18,331	24,492
Net cash used in financing activities	(158,718)	(199,123)	(151,568)
Effect of exchange rate changes on cash and cash equivalents	(7,039)	7,274	(4,143)
Net increase (decrease) in cash and cash equivalents	7,359	(14,056)	(20,579)
Cash and cash equivalents at beginning of year	181,685	195,741	216,320
Cash and cash equivalents at end of year	189,044	181,685	195,741
Cash paid during the year for income taxes	73,219	36,869	38,450
Dividends declared, not paid	13,727	12,165	10,586
Stock issued for acquisition of business	$ 3,974