Note 15 - Employee Stock Option and Retirement Plans - Summary of Share-based Awards Available for Grant (Details) - shares		12 Months Ended
		Aug. 31, 2019	Aug. 31, 2018		Aug. 31, 2017
LTIP [Member]
Balance (in shares)		6,298,000	897,000		1,491,000
Share-based awards canceled/forfeited (in shares)	[1]	433,000	252,000		566,000
Increase in the number of shares available for issuance (in shares)			5,750,000
Balance (in shares)		6,067,000	6,298,000		897,000
LTIP [Member] | Non Performance Based [Member]
Granted (in shares)		(481,000)	(575,000)		(713,000)
LTIP [Member] | Performance Shares [Member]
Granted (in shares)			(17,000)		(291,000)
LTIP [Member] | Non-Employee Director Grant [Member]
Granted (in shares)			0		0
LTIP [Member] | Restricted Stock [Member]
Granted (in shares)		(183,000)	(9,000)	[2]	(156,000)	[2]
Director Plan [Member]
Balance (in shares)		282,000	42,000		66,000
Share-based awards canceled/forfeited (in shares)	[1]	2,000	9,000		0
Increase in the number of shares available for issuance (in shares)			250,000
Balance (in shares)		263,956	282,000		42,000
Director Plan [Member] | Non Performance Based [Member]
Granted (in shares)		(20,000)	0		0
Director Plan [Member] | Performance Shares [Member]
Granted (in shares)			0		0
Director Plan [Member] | Non-Employee Director Grant [Member]
Granted (in shares)			(19,000)		(24,000)
Director Plan [Member] | Restricted Stock [Member]
Granted (in shares)		0	0	[2]	0	[2]

[1] Under the Company's Option Plan, for each restricted stock award canceled/forfeited, an equivalent of 2.5 shares is added back to the available share-based awards balance.

[2] Each restricted stock award granted is equivalent to 2.5 shares granted under the Company's Option Plan.