Note 14 - Employee Stock Option and Retirement Plans (Details Textual) - USD ($) | 1 Months Ended | 3 Months Ended | 9 Months Ended | 47 Months Ended | | |
Jul. 31, 2012 | May 31, 2016 | Nov. 30, 2015 | May 31, 2015 | Feb. 28, 2015 | May 31, 2016 | May 31, 2015 | May 31, 2016 | Feb. 29, 2016 | Aug. 31, 2015 |
Employee Stock Option [Member] | The 2004 Stock Option and Award Plan [Member] | Minimum [Member] | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period | | | | | | | 7 years | | | | |
Employee Stock Option [Member] | The 2004 Stock Option and Award Plan [Member] | Maximum [Member] | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period | | | | | | | 10 years | | | | |
Employee Stock Option [Member] | The 2004 Stock Option and Award Plan [Member] | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period | | | | | | | 5 years | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross | | | | | | | 1,152,179 | | | | |
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price | | | | | | | $ 168.51 | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number | | 3,753,264 | | | | | 3,753,264 | | 3,753,264 | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price | | $ 125.52 | | | | | $ 125.52 | | $ 125.52 | | |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized | | $ 54,200,000 | | | | | $ 54,200,000 | | $ 54,200,000 | | |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition | | | | | | | 3 years 109 days | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number | | 1,100,000 | | | | | 1,100,000 | | 1,100,000 | | 1,400,000 |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price | | $ 86.61 | | | | | $ 86.61 | | $ 86.61 | | $ 78.70 |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value | | $ 80,800,000 | | | | | $ 80,800,000 | | $ 80,800,000 | | $ 107,100,000 |
Employee Stock Option [Member] | | | | | | | | | | | |
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price | | $ 152.10 | $ 170.21 | | $ 159.14 | $ 147.05 | $ 168.51 | $ 137.52 | | | |
Performance Shares [Member] | Code Red, Inc. [Member] | Share-based Compensation Award, Tranche One [Member] | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period | | | | | | 2 years | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross | | | | | | 68,761 | | | | | |
Performance Shares [Member] | Code Red, Inc. [Member] | Share-based Compensation Award, Tranche Two [Member] | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period | | | | | | 4 years | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross | | | | | | 68,761 | | | | | |
Performance Shares [Member] | Code Red, Inc. [Member] | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period | | | | | | 4 years | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross | | | | | | 137,522 | | | | | |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized | | $ 1,600,000 | | | | | $ 1,600,000 | | 1,600,000 | | |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition | | | | | | | 2 years 255 days | | | | |
Performance Shares [Member] | Portware LLC [Member] | Share-based Compensation Award, Tranche One [Member] | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage | | | 40.00% | | | | | | | | |
Performance Shares [Member] | Portware LLC [Member] | Share-based Compensation Award, Tranche Two [Member] | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage | | | 20.00% | | | | | | | | |
Performance Shares [Member] | Portware LLC [Member] | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross | | | 530,418 | | | | | | | | |
Performance Shares [Member] | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross | 241,546 | | 530,418 | | | 137,522 | | | | | |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized | | 500,000 | | | | | $ 500,000 | | $ 500,000 | | |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition | | | | | | | 1 year 73 days | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage | 20.00% | | | | | | | | 60.00% | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Number of Shares | | | | | | | | | 144,942 | | |
Restricted Stock [Member] | The 2004 Stock Option and Award Plan [Member] | Share-based Compensation Award, Tranche One [Member] | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage | | | 40.00% | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Measurement Period | | | 5 years | | | | | | | | |
Restricted Stock [Member] | The 2004 Stock Option and Award Plan [Member] | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period | | | | | | | 4 years 328 days | | | | |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized | | $ 28,400,000 | | | | | $ 28,400,000 | | $ 28,400,000 | | |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition | | | | | | | 3 years 146 days | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period | | | | | | | 93,375 | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value | | | | | | | $ 159.42 | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number | | 341,333 | | | | | 341,333 | | 341,333 | | |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period | | | 37,079 | | | | | | | | |
Restricted Stock [Member] | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period | | | 93,000 | | | | 93,375 | 49,158 | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value | | | $ 159.46 | | | | $ 159.42 | $ 135.96 | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number | | 341,000 | 368,000 | | | | 341,000 | | 341,000 | 358,000 | 313,000 |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period | | 15,000 | 37,000 | [1] | | | 51,762 | 68,178 | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Share Equivalent | | 2.5 | | | | | 2.5 | | 2.5 | | |
The 2004 Stock Option and Award Plan [Member] | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value | | $ 9,300,000 | | | $ 32,100,000 | | $ 43,000,000 | $ 70,900,000 | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number | | 3,753,000 | 3,876,000 | | | | 3,753,000 | | 3,753,000 | 3,788,000 | 3,117,000 |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price | | $ 125.52 | $ 122.06 | | | | $ 125.52 | | $ 125.52 | $ 123.24 | $ 100.71 |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized | | $ 82,500,000 | | | | | $ 82,500,000 | | $ 82,500,000 | | |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition | | | | | | | 3 years 109 days | | | | |
Share Price | | $ 159.07 | | | | | $ 159.07 | | $ 159.07 | | |
Share-based Compensation Arrangement by Share-based Payment Award, Purchase Price of Common Stock, Percent | | | | | | | 85.00% | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Employee Subscription Rate | | 10.00% | | | | | 10.00% | | 10.00% | | |
Stock Issued During Period, Shares, Employee Stock Purchase Plans | | 17,538 | | | 13,877 | | 53,711 | 47,085 | | | |
Treasury Stock Acquired, Average Cost Per Share | | $ 131.57 | | | $ 132.48 | | $ 129.83 | $ 118.82 | | | |
Common Stock, Capital Shares Reserved for Future Issuance | | 427,905 | | | | | 427,905 | | 427,905 | | |
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent | | | | | | | 60.00% | | | | |
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay | | | | | | | 4.00% | | | | |
Defined Contribution Plan, Employer Matching Contribution, Vesting Period | | | | | | | 5 years | | | | |
Defined Contribution Plan, Employer Discretionary Contribution Amount | | | | | | | $ 7,100,000 | $ 6,300,000 | | | |
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[1] | All of the 37,079 restricted stock awards that vested during the first quarter of fiscal 2016 related to awards granted on November 8, 2010. The remaining 40% of these restricted stock awards cliff vested after five years on November 8, 2015 and were amortized to expense over the vesting period using the straight-line attribution method. |