Note 17 - Income Taxes - Provision for Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Aug. 31, 2018	Aug. 31, 2018	Aug. 31, 2018	Aug. 31, 2017	Aug. 31, 2017	Aug. 31, 2017	Aug. 31, 2016	Aug. 31, 2016	Aug. 31, 2016	[1]
U.S. operations		$ 199,654			$ 218,650			$ 353,434
Non-U.S. operations		152,184			125,662			107,559
Income before income taxes		351,838			344,312			460,993
U.S. operations		65,778			65,403			106,671
Non-U.S. operations		18,975			20,650			15,507
Total provision for income taxes		$ 84,753			$ 86,053			$ 122,178
Effective tax rate	24.10%		24.10%	25.00%		25.00%	26.50%		26.50%

[1] The fiscal 2016 effective tax rate of 26.5% includes income tax benefits of $10.5 million primarily from the permanent reenactment of the U.S. Federal R&D Tax Credit ("R&D tax credit") in December 2015, finalizing the fiscal 2015 tax returns and other discrete items. The reenactment of the R&D tax credit was retroactive to January 1, 2015, and eliminates the yearly uncertainty surrounding the extension of the credit.