Note 14 - Summary of Stock Option Activity (Details) - $ / shares	3 Months Ended						9 Months Ended
	May 31, 2016	Feb. 29, 2016	Nov. 30, 2015	May 31, 2015	Feb. 28, 2015	Nov. 30, 2014	May 31, 2016
Non Performance Based [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	103,903	4,073	513,785	61,210	25,075	462,913
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price	$ 152.10	$ 150.81	$ 175.20	$ 159.14		$ 131.31
Performance Based [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross		23,000	530,000
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price		$ 146.82	$ 165.37
Balance (in shares)	3,788,000	3,876,000	3,117,000				3,117,000
Balance (in dollars per share)	$ 123.24	$ 122.06	$ 100.71				$ 100.71
Exercised (in shares)	(127,000)	(70,000)	(277,000)
Exercised (in dollars per share)	$ 78.63	$ 63.77	$ 63.72
Forfeited (in shares)	(12,000)	(45,000)	(8,000)
Forfeited (in dollars per share)	$ 132.68	$ 127.82	$ 108.32
Balance (in shares)	3,753,000	3,788,000	3,876,000				3,753,000
Balance (in dollars per share)	$ 125.52	$ 123.24	$ 122.06				$ 125.52