Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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Unrecognized cost of unvested share-based compensation awards.

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Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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Gross number of share options (or share units) granted during the period.

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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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Number of shares issued during the period as a result of an employee stock purchase plan.

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Note 14 - Stock-based Compensation (Details Textual) - USD ($) $ / shares in Units, $ in Thousands			3 Months Ended					6 Months Ended			18 Months Ended
	Jan. 15, 2019	Jan. 12, 2018	Feb. 28, 2019	Nov. 30, 2018	Aug. 31, 2018	Feb. 28, 2018	Nov. 30, 2017	Feb. 28, 2019	Aug. 31, 2018	Feb. 28, 2018	Feb. 28, 2019
Allocated Share-based Compensation Expense, Total			$ 7,700			$ 7,900		$ 16,100		$ 15,400
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Total			$ 87,200					87,200			$ 87,200
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition			3 years 109 days
Employee Service Share-based Compensation, Allocation of Recognized Period Costs, Capitalized Amount			$ 0		$ 0			$ 0	$ 0
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price			$ 207.84			$ 192.11		$ 221.74		$ 190.04
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value			$ 53.18			$ 48.82		$ 56.72		$ 48.29
Stock Issued During Period, Shares, Employee Stock Purchase Plans			12,624			14,805		25,719			34,394
Director Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	20,576	18,963	21,000
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price			$ 207.88
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 42.77	$ 38.76
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant			263,956	282,000	282,000			263,956	282,000		263,956
The 2008 Employee Stock Purchase Plan [Member]
Allocated Share-based Compensation Expense, Total			$ 500			$ 500		$ 1,000		$ 1,100
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price			$ 199.36			$ 171.23		$ 198.33		$ 150.25
Stock Issued During Period, Shares, Employee Stock Purchase Plans			12,624			14,805		25,719		34,394
Non Performance Based [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross			6,115	454,598		15,363	553,942
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price			$ 207.84	$ 221.93		$ 192.11	$ 189.98
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value			53.18	56.77		$ 48.82	$ 48.27
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross								41,153
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value				$ 212.66				$ 212.66		$ 182.17
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period				41,000						961