Note 13 - Employee Stock Option and Retirement Plans (Details) - USD ($) $ / shares in Units, $ in Millions | Oct. 23, 2014 | Aug. 31, 2014 | Sep. 17, 2013 | Jul. 31, 2012 | May. 31, 2015 | Feb. 28, 2015 | Nov. 30, 2014 | May. 31, 2014 | Feb. 28, 2014 | Nov. 30, 2013 | Aug. 31, 2013 | Feb. 28, 2015 | May. 31, 2015 | May. 31, 2014 | Aug. 31, 2014 | May. 29, 2015 | Dec. 16, 2014 |
Note 13 - Employee Stock Option and Retirement Plans (Details) [Line Items] | | | | | | | | | | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross | | | | | 61,000 | | | | 463,000 | | | | | | | 0 | | | | |
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in Dollars per share) | | | | | $ 159.14 | | | | $ 131.31 | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number | | 3,482,000 | | | 3,254,000 | | 3,540,000 | | 3,798,000 | | | | | | 3,540,000 | 3,254,000 | | 3,482,000 | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price (in Dollars per share) | | $ 79.67 | | | $ 96.05 | | $ 91.67 | | $ 85.98 | | | | | | $ 91.67 | $ 96.05 | | $ 79.67 | | |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized (in Dollars) | | | | | $ 60.3 | | | | | | | | | | | $ 60.3 | | | | |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition | | | | | | | | | | | | | | | | 3 years 109 days | | | | |
Share Price (in Dollars per share) | | | | | | | | | | | | | | | | | | | $ 165.17 | |
Common Stock, Capital Shares Reserved for Future Issuance | | | | | | | | | | | | | | | | | | | | 500,000 |
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% | | | | |
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent | | | | | | | | | | | | | | | | 60.00% | | | | |
Defined Contribution Plan, Employer Matching Contribution, Vesting Period | | | | | | | | | | | | | | | | 5 years | | | | |
Defined Contribution Plan, Employer Discretionary Contribution Amount (in Dollars) | | | | | | | | | | | | | | | | $ 6.3 | $ 5.7 | | | |
2004 Stock Option and Award Plan [Member] | | | | | | | | | | | | | | | | | | | | |
Note 13 - Employee Stock Option and Retirement Plans (Details) [Line Items] | | | | | | | | | | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross | | | | | | | | | | | | | | | | 686,720 | | | | |
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in Dollars per share) | | | | | | | | | | | | | | | | $ 137.52 | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number | | | | | 3,253,586 | | | | | | | | | | | 3,253,586 | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price (in Dollars per share) | | | | | $ 96.05 | | | | | | | | | | | $ 96.05 | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value (in Dollars) | | | | | $ 32.1 | | | | | | $ 6.9 | | | | | $ 70.9 | $ 22.9 | | | |
Employee Stock Option [Member] | | | | | | | | | | | | | | | | | | | | |
Note 13 - Employee Stock Option and Retirement Plans (Details) [Line Items] | | | | | | | | | | | | | | | | | | | | |
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in Dollars per share) | | | | | $ 159.14 | | | | | | | | | | | $ 137.52 | $ 106.69 | | | |
Employee Stock Option [Member] | 2004 Stock Option and Award Plan [Member] | | | | | | | | | | | | | | | | | | | | |
Note 13 - Employee Stock Option and Retirement Plans (Details) [Line Items] | | | | | | | | | | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period | | | | | | | | | | | | | | | | 5 years | | | | |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized (in Dollars) | | | | | $ 37.5 | | | | | | | | | | | $ 37.5 | | | | |
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, Options, Exercisable, Number | | 1,900,000 | | | 1,400,000 | | | | | | | | | | | 1,400,000 | | 1,900,000 | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price (in Dollars per share) | | $ 68.78 | | | $ 77.83 | | | | | | | | | | | $ 77.83 | | $ 68.78 | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value (in Dollars) | | $ 111.3 | | | $ 118.8 | | | | | | | | | | | $ 118.8 | | $ 111.3 | | |
Performance Shares [Member] | | | | | | | | | | | | | | | | | | | | |
Note 13 - Employee Stock Option and Retirement Plans (Details) [Line Items] | | | | | | | | | | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross | | | | 241,546 | | | 137,522 | | | | | 165,949 | 36,695 | | | | | | | |
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in Dollars per share) | | | | | | | $ 148.52 | | | | | | | | | | | | | |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized (in Dollars) | | | | | 0.7 | | | | | | | | | | | $ 0.7 | | | | |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition | | | | | | | | | | | | | | | | 2 years 73 days | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage | | | | 20.00% | | | | | | | | | | | | | | | | |
Performance Shares [Member] | Share-based Compensation Award, Tranche One [Member] | | | | | | | | | | | | | | | | | | | | |
Note 13 - Employee Stock Option and Retirement Plans (Details) [Line Items] | | | | | | | | | | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage | | | | | | | | | | | | | | 20.00% | | 20.00% | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Number of Shares | | | | | | | | | | | | | | 48,314 | | | | | | |
Performance Shares [Member] | Share-based Compensation Award, Tranche Two [Member] | | | | | | | | | | | | | | | | | | | | |
Note 13 - Employee Stock Option and Retirement Plans (Details) [Line Items] | | | | | | | | | | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage | | 20.00% | | | | | | | | | | | | | | | | | | |
Performance Shares [Member] | Code Red, Inc. [Member] | | | | | | | | | | | | | | | | | | | | |
Note 13 - Employee Stock Option and Retirement Plans (Details) [Line Items] | | | | | | | | | | | | | | | | | | | | |
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 (in Dollars) | | | | | 2.2 | | | | | | | | | | | $ 2.2 | | | | |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition | | | | | | | | | | | | | | | | 3 years 255 days | | | | |
Performance Shares [Member] | Code Red, Inc. [Member] | Share-based Compensation Award, Tranche One [Member] | | | | | | | | | | | | | | | | | | | | |
Note 13 - Employee Stock Option and Retirement Plans (Details) [Line Items] | | | | | | | | | | | | | | | | | | | | |
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 Award, Tranche Two [Member] | | | | | | | | | | | | | | | | | | | | |
Note 13 - Employee Stock Option and Retirement Plans (Details) [Line Items] | | | | | | | | | | | | | | | | | | | | |
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] | Matrix Data Limited [Member] | | | | | | | | | | | | | | | | | | | | |
Note 13 - Employee Stock Option and Retirement Plans (Details) [Line Items] | | | | | | | | | | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross | | | | | | | | | | | | | | | | | | 165,949 | | |
Share-Based Compensation Arrangement by Share-Based Payment Award, Options Measurement Period | | | | | | | | | | | | | | | | | | 5 years | | |
Performance Shares [Member] | Revere Data, LLC [Member] | | | | | | | | | | | | | | | | | | | | |
Note 13 - Employee Stock Option and Retirement Plans (Details) [Line Items] | | | | | | | | | | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross | | | | | | | | | | | | | | | | | | 36,695 | | |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized (in Dollars) | | | | | $ 0.4 | | | | | | | | | | | $ 0.4 | | | | |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition | | | | | | | | | | | | | | | | 3 years 73 days | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number | | | | | 18,553 | | | | | | | | | | | 18,553 | | | | |
Restricted Stock [Member] | | | | | | | | | | | | | | | | | | | | |
Note 13 - Employee Stock Option and Retirement Plans (Details) [Line Items] | | | | | | | | | | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period | | | | | 38,000 | | 1,000 | | 10,000 | | | | | | | 49,158 | 204,124 | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value (in Dollars per share) | | | | | | | | | | | | | | | | $ 135.96 | $ 101.95 | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number | | 368,000 | | | 339,000 | | 357,000 | | 324,000 | | | | | | 357,000 | 339,000 | | 368,000 | | |
Restricted Stock [Member] | 2004 Stock Option and Award Plan [Member] | | | | | | | | | | | | | | | | | | | | |
Note 13 - Employee Stock Option and Retirement Plans (Details) [Line Items] | | | | | | | | | | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period | | | | | | | | | | | | | | | | 3 years 328 days | | | | |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized (in Dollars) | | | | | $ 22.7 | | | | | | | | | | | $ 22.7 | | | | |
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, Equity Instruments Other than Options, Grants in Period | | | | | 2,000 | [1] | 95,000 | [1] | 26,000 | [1] | | | | | | 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 (in Dollars per share) | | | | | | | | | | | | | | | | $ 135.96 | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number | | | | | 339,298 | | | | | | | | | | | 339,298 | | | | |
Restricted Stock [Member] | Code Red, Inc. [Member] | | | | | | | | | | | | | | | | | | | | |
Note 13 - Employee Stock Option and Retirement Plans (Details) [Line Items] | | | | | | | | | | | | | | | | | | | | |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized (in Dollars) | | | | | $ 0.1 | | | | | | | | | | | $ 0.1 | | | | |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition | | | | | | | | | | | | | | | | 1 year 255 days | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number | | | | | | | 690 | | | | | | | | 690 | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period | | | | | | | | | | | | | | | 1,724 | | | | | |
Performance Based Stock Options Outstanding Expected to be Forfeited | | | | | 1,034 | | | | | | | | | | | 1,034 | | | | |
Restricted Stock [Member] | Revere Data, LLC [Member] | | | | | | | | | | | | | | | | | | | | |
Note 13 - Employee Stock Option and Retirement Plans (Details) [Line Items] | | | | | | | | | | | | | | | | | | | | |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized (in Dollars) | | | | | $ 0.3 | | | | | | | | | | | $ 0.3 | | | | |
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition | | | | | | | | | | | | | | | | 3 years 73 days | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested and Expected to Vest, Outstanding, Number | | | 3,872 | | | | | | | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period | | | 7,744 | | | | | | | | | | | | | | | | | |
Performance Based Stock Options Outstanding Expected to be Forfeited | | | | | 3,872 | | | | | | | | | | | 3,872 | | | | |
2008 Employee Stock Purchase Plan [Member] | | | | | | | | | | | | | | | | | | | | |
Note 13 - Employee Stock Option and Retirement Plans (Details) [Line Items] | | | | | | | | | | | | | | | | | | | | |
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price (in Dollars per share) | | | | | $ 132.48 | | | | | | $ 88.55 | | | | | $ 118.82 | $ 88.33 | | | |
Common Stock, Capital Shares Reserved for Future Issuance | | | | | 497,796 | | | | | | | | | | | 497,796 | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized | 500,000 | | | | | | | | | | | | | | | | | | | |
Stock Issued During Period, Shares, Employee Stock Purchase Plans | | | | | 13,877 | | | | | | 18,068 | | | | | 47,085 | 54,597 | | | |
Treasury Stock Acquired, Average Cost Per Share (in Dollars per share) | | | | | $ 132.48 | | | | | | $ 88.55 | | | | | $ 118.82 | $ 88.33 | | | |
Minimum [Member] | Employee Stock Option [Member] | 2004 Stock Option and Award Plan [Member] | | | | | | | | | | | | | | | | | | | | |
Note 13 - Employee Stock Option and Retirement Plans (Details) [Line Items] | | | | | | | | | | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period | | | | | | | | | | | | | | | | 7 years | | | | |
Maximum [Member] | Employee Stock Option [Member] | 2004 Stock Option and Award Plan [Member] | | | | | | | | | | | | | | | | | | | | |
Note 13 - Employee Stock Option and Retirement Plans (Details) [Line Items] | | | | | | | | | | | | | | | | | | | | |
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period | | | | | | | | | | | | | | | | 10 years | | | | |
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[1] | Each restricted stock award granted is equivalent to 2.5 shares granted under the Company's option plan. |