Consolidated Statements of Cash Flows $ in Thousands	12 Months Ended
	Aug. 31, 2019 USD ($)	Aug. 31, 2018 USD ($)	Aug. 31, 2017 USD ($)
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 352,790	$ 267,085	$ 258,259
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	60,463	57,285	48,294
Stock-based compensation expense	32,400	31,516	34,183
Deferred income taxes	(2,278)	(1,910)	4,879
Loss on sale of assets	196	140	1,282
Tax benefits from share-based payment arrangements	0	0	(10,331)
Changes in assets and liabilities, net of effects of acquisitions
Accounts receivable, net of reserves	10,205	(8,417)	(29,503)
Accounts payable and accrued expenses	(2,290)	12,077	(2,226)
Accrued compensation	(1,743)	5,735	6,427
Deferred fees	458	6,035	(229)
Taxes payable, net of prepaid taxes	(19,238)	27,659	7,877
Other, net	(3,827)	(11,537)	1,613
Net cash provided by operating activities	427,136	385,668	320,527
CASH FLOWS FROM INVESTING ACTIVITIES:
Acquisition of businesses and investments, net of cash and cash equivalents acquired	0	(15,000)	(303,086)
Purchases of investments	(11,135)	(12,470)	(30,757)
Proceeds from maturity or sale of investments	14,405	12,459	23,399
Purchases of property, equipment and leasehold improvements	(59,370)	(33,520)	(36,862)
Net cash used in investing activities	(56,100)	(48,531)	(347,306)
CASH FLOWS FROM FINANCING ACTIVITIES
Dividend payments	(100,052)	(89,408)	(80,898)
Repurchase of common stock	(220,372)	(303,955)	(260,978)
Repayment of debt	(575,000)	0	(365,000)
Proceeds from debt	575,000	0	640,000
Proceeds from employee stock plans	107,051	71,610	50,045
Tax benefits from share-based payment arrangements	0	0	10,331
Other financing activities, net	(901)	1,716	(1,661)
Net cash used in financing activities	(214,274)	(320,037)	(8,161)
Effect of exchange rate changes on cash and cash equivalents	(5,586)	(3,208)	1,264
Net increase (decrease) in cash and cash equivalents	151,176	13,892	(33,676)
Cash and cash equivalents at beginning of period	208,623	194,731	228,407
Cash and cash equivalents at end of period	359,799	208,623	194,731
Supplemental Disclosure of Cash Flow Information
Cash paid during the year for interest	19,509	15,676	8,466
Cash paid during the year for income taxes, net of refunds	89,997	68,707	74,788
Supplemental Disclosure of Non-Cash Transactions
Dividends declared, not paid	$ 27,445	$ 24,443	$ 21,853