Note 14 - Summary of Restricted Stock Award (Details) - Restricted Stock [Member] - $ / shares	3 Months Ended				9 Months Ended
	May 31, 2016	Feb. 29, 2016	Nov. 30, 2015		May 31, 2016	May 31, 2015
Balance (in shares)	358,000	368,000	313,000		313,000
Balance (in dollars per share)	$ 119.55	$ 119.44	$ 103.34		$ 103.34
Granted (in shares)			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
Vested(1) (in shares)	(15,000)		(37,000)	[1]	(51,762)	(68,178)
Vested(1) (in dollars per share)	$ 85.80		$ 84.38	[1]
Canceled/forfeited (in shares)	(2,000)	(10,000)	(1,000)
Canceled/forfeited (in dollars per share)	$ 121.43	$ 115.03	$ 97.92
Balance (in shares)	341,000	358,000	368,000		341,000
Balance (in dollars per share)	$ 121.01	$ 119.55	$ 119.44		$ 121.01

[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.