Note 13 - Employee Stock Option and Retirement Plans (Details) - Exercise Price Ranges Of Outstanding And Exercisable Options (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Aug. 31, 2013	Aug. 31, 2012	Aug. 31, 2011	Aug. 31, 2010
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices Per Share Lower Limit	$ 88.40
Range of Exercise Prices Per Share Upper Limit	$ 103.30
Number Outstanding (in Shares)	4,729	6,083	6,132	6,451
Weighted Average Remaining Years of Contractual Life Outstanding	5 years 328 days
Weighted Average Exercise Price Per Share Outstanding	$ 75.95	$ 64.76	$ 57.28	$ 47.73
Aggregate Intrinsic Value Outstanding (in Dollars)	$ 124,861
Number Exercisable (in Shares)	1,925	2,858	2,643
Weighted Average Exercise Price Per Share Exercisable	$ 59.70	$ 48.44	$ 38.99
Aggregate Intrinsic Value Exercisable (in Dollars)	82,082
$24.49 - $59.36 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices Per Share Lower Limit	$ 24.49
Range of Exercise Prices Per Share Upper Limit	$ 59.36
Number Outstanding (in Shares)	782
Weighted Average Remaining Years of Contractual Life Outstanding	1 year 146 days
Weighted Average Exercise Price Per Share Outstanding	$ 39.96
Aggregate Intrinsic Value Outstanding (in Dollars)	48,801
Number Exercisable (in Shares)	759
Weighted Average Exercise Price Per Share Exercisable	$ 40.03
Aggregate Intrinsic Value Exercisable (in Dollars)	47,293
$61.65 - $65.67 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices Per Share Lower Limit	$ 61.65
Range of Exercise Prices Per Share Upper Limit	$ 65.67
Number Outstanding (in Shares)	661
Weighted Average Remaining Years of Contractual Life Outstanding	2 years 6 months
Weighted Average Exercise Price Per Share Outstanding	$ 64.44
Aggregate Intrinsic Value Outstanding (in Dollars)	25,046
Number Exercisable (in Shares)	379
Weighted Average Exercise Price Per Share Exercisable	$ 65.44
Aggregate Intrinsic Value Exercisable (in Dollars)	13,992
$66.46 - $67.41 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices Per Share Lower Limit	$ 66.46
Range of Exercise Prices Per Share Upper Limit	$ 67.41
Number Outstanding (in Shares)	696
Weighted Average Remaining Years of Contractual Life Outstanding	3 years 36 days
Weighted Average Exercise Price Per Share Outstanding	$ 66.47
Aggregate Intrinsic Value Outstanding (in Dollars)	24,975
Number Exercisable (in Shares)	495
Weighted Average Exercise Price Per Share Exercisable	$ 66.47
Aggregate Intrinsic Value Exercisable (in Dollars)	17,749
$87.26 - $91.06 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices Per Share Lower Limit	$ 87.26
Range of Exercise Prices Per Share Upper Limit	$ 91.06
Number Outstanding (in Shares)	551
Weighted Average Remaining Years of Contractual Life Outstanding	8 years 146 days
Weighted Average Exercise Price Per Share Outstanding	$ 90.08
Aggregate Intrinsic Value Outstanding (in Dollars)	6,761
Number Exercisable (in Shares)	142
Weighted Average Exercise Price Per Share Exercisable	$ 88.74
Aggregate Intrinsic Value Exercisable (in Dollars)	1,935
$92.22 - $92.55 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices Per Share Lower Limit	$ 92.22
Range of Exercise Prices Per Share Upper Limit	$ 92.55
Number Outstanding (in Shares)	1,591
Weighted Average Remaining Years of Contractual Life Outstanding	9 years 73 days
Weighted Average Exercise Price Per Share Outstanding	$ 92.22
Aggregate Intrinsic Value Outstanding (in Dollars)	16,111
Weighted Average Exercise Price Per Share Exercisable	$ 92.22
$94.84 - $103.30 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices Per Share Lower Limit	$ 94.84
Range of Exercise Prices Per Share Upper Limit	$ 103.30
Number Outstanding (in Shares)	448
Weighted Average Remaining Years of Contractual Life Outstanding	8 years
Weighted Average Exercise Price Per Share Outstanding	$ 95.28
Aggregate Intrinsic Value Outstanding (in Dollars)	3,167
Number Exercisable (in Shares)	150
Weighted Average Exercise Price Per Share Exercisable	$ 94.92
Aggregate Intrinsic Value Exercisable (in Dollars)	$ 1,113