Note 2 - Common Stock Outstanding and Earnings Per Share (Details Textual) - USD ($) $ / shares in Units, $ in Thousands			3 Months Ended			6 Months Ended
	Apr. 07, 2020	Feb. 21, 2020	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Mar. 31, 2020	Sep. 18, 2019
Stock Repurchase Program, Number of Shares Authorized to be Repurchased (in shares)		1,500,000					1,000,000
Stock Repurchase Program, Extension Period (Year)		1 year
Stock Repurchased During Period, Shares (in shares)			1,351,922	90,501		1,500,000
Payments for Repurchase of Common Stock			$ 12,230			$ 13,600
Payments for Repurchase of Common Stock, Average Price Per Share (in dollars per share)						$ 9.11
Subsequent Event [Member]
Stock Repurchased During Period, Shares (in shares)	57,577