Note 16 - Stockholders' Equity (Details Textual) - USD ($) $ / shares in Thousands	3 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Sep. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	83,343	1,600
Gross Proceeds from Stock Options Exercised	$ 144,214	$ 2,528
Common Stock, Dividends, Per Share, Declared	$ 0	$ 0
Share Buyback Program [Member]
Stock Repurchase Program, Authorized Amount		$ 5,000,000	$ 4,000,000
Stock Repurchased and Retired During Period, Shares	0	588,425
Stock Repurchased During Period, Value		$ 1,621,022