Note 15 - Income Taxes (Details Textual) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Feb. 28, 2018	Dec. 31, 2018	Aug. 31, 2018	Dec. 31, 2017	Aug. 31, 2017
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent				35.00%
Undistributed Earnings of Foreign Subsidiaries	$ 250,000
Income Tax Expense (Benefit), Continuing Operations, Transition Tax	23,200
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability	2,200
Unrecognized Tax Benefits	11,078				$ 11,484
Unrecognized Tax Benefits, Interest on Income Taxes Accrued	$ 1,600
Scenario, Forecast [Member]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent		21.00%	25.70%