Note 14 - 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, 2014	Aug. 31, 2013	Aug. 31, 2012	Aug. 31, 2011
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices - Minimum	$ 87.26
Range of Exercise Prices - Maximum	$ 110.31
Outstanding - Number Outstanding (in Shares)	3,482	4,729	6,083	6,132
Outstanding - Weighted Average Remaining Years of Contractual Life	5 years 73 days
Outstanding - Weighted Average Exercise Price Per Share	$ 79.67	$ 75.95	$ 64.76	$ 57.28
Outstanding - Aggregate Intrinsic Value (in Dollars)	$ 166,223
Exercisable - Number Exercisable (in Shares)	1,899	1,925	2,858
Exercisable - Weighted Average Exercise Price Per Share	$ 68.78	$ 59.70	$ 48.44
Exercisable - Aggregate Intrinsic Value (in Dollars)	111,307
Range 1 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices - Minimum	$ 29.00
Range of Exercise Prices - Maximum	$ 58.78
Outstanding - Number Outstanding (in Shares)	356
Outstanding - Weighted Average Remaining Years of Contractual Life	328 days
Outstanding - Weighted Average Exercise Price Per Share	$ 35.28
Outstanding - Aggregate Intrinsic Value (in Dollars)	32,845
Exercisable - Number Exercisable (in Shares)	356
Exercisable - Weighted Average Exercise Price Per Share	$ 35.28
Exercisable - Aggregate Intrinsic Value (in Dollars)	32,845
Range 2 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices - Minimum	$ 63.09
Range of Exercise Prices - Maximum	$ 65.67
Outstanding - Number Outstanding (in Shares)	527
Outstanding - Weighted Average Remaining Years of Contractual Life	1 year 255 days
Outstanding - Weighted Average Exercise Price Per Share	$ 64.23
Outstanding - Aggregate Intrinsic Value (in Dollars)	33,265
Exercisable - Number Exercisable (in Shares)	386
Exercisable - Weighted Average Exercise Price Per Share	$ 64.65
Exercisable - Aggregate Intrinsic Value (in Dollars)	24,211
Range 3 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices - Minimum	$ 66.46
Range of Exercise Prices - Maximum	$ 66.81
Outstanding - Number Outstanding (in Shares)	565
Outstanding - Weighted Average Remaining Years of Contractual Life	2 years 36 days
Outstanding - Weighted Average Exercise Price Per Share	$ 66.47
Outstanding - Aggregate Intrinsic Value (in Dollars)	34,411
Exercisable - Number Exercisable (in Shares)	528
Exercisable - Weighted Average Exercise Price Per Share	$ 66.47
Exercisable - Aggregate Intrinsic Value (in Dollars)	32,188
Range 4 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices - Minimum	$ 87.26
Range of Exercise Prices - Maximum	$ 91.06
Outstanding - Number Outstanding (in Shares)	489
Outstanding - Weighted Average Remaining Years of Contractual Life	6 years 6 months
Outstanding - Weighted Average Exercise Price Per Share	$ 90.21
Outstanding - Aggregate Intrinsic Value (in Dollars)	18,192
Exercisable - Number Exercisable (in Shares)	229
Exercisable - Weighted Average Exercise Price Per Share	$ 89.80
Exercisable - Aggregate Intrinsic Value (in Dollars)	8,599
Range 5 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices - Minimum	$ 92.22
Range of Exercise Prices - Maximum	$ 92.55
Outstanding - Number Outstanding (in Shares)	751
Outstanding - Weighted Average Remaining Years of Contractual Life	8 years 36 days
Outstanding - Weighted Average Exercise Price Per Share	$ 92.22
Outstanding - Aggregate Intrinsic Value (in Dollars)	26,416
Exercisable - Number Exercisable (in Shares)	195
Exercisable - Weighted Average Exercise Price Per Share	$ 92.23
Exercisable - Aggregate Intrinsic Value (in Dollars)	6,852
Range 6 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices - Minimum	$ 94.84
Range of Exercise Prices - Maximum	$ 103.30
Outstanding - Number Outstanding (in Shares)	542
Outstanding - Weighted Average Remaining Years of Contractual Life	7 years 6 months
Outstanding - Weighted Average Exercise Price Per Share	$ 96.90
Outstanding - Aggregate Intrinsic Value (in Dollars)	16,535
Exercisable - Number Exercisable (in Shares)	205
Exercisable - Weighted Average Exercise Price Per Share	$ 95.11
Exercisable - Aggregate Intrinsic Value (in Dollars)	6,612
Range 7 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices - Minimum	$ 107.65
Range of Exercise Prices - Maximum	$ 110.31
Outstanding - Number Outstanding (in Shares)	252
Outstanding - Weighted Average Remaining Years of Contractual Life	9 years 36 days
Outstanding - Weighted Average Exercise Price Per Share	$ 109.32
Outstanding - Aggregate Intrinsic Value (in Dollars)	4,559
Exercisable - Number Exercisable (in Shares)	0
Exercisable - Weighted Average Exercise Price Per Share	$ 109.32
Exercisable - Aggregate Intrinsic Value (in Dollars)	$ 0