Note 21 - Subsequent Events (Details Textual) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		8 Months Ended	9 Months Ended		17 Months Ended
	Nov. 04, 2020	Mar. 31, 2020	Sep. 30, 2019	Dec. 31, 2019	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020
Treasury Stock, Value, Acquired, Cost Method			$ 4,692		$ 12,880	$ 36,301
May 2019 Repurchase Program [Member]
Treasury Stock, Shares, Acquired (in shares)		400,000		741,934			1,141,934
Treasury Stock, Value, Acquired, Cost Method		$ 12,900		$ 26,400			$ 39,300
Treasury Stock Acquired, Average Cost Per Share (in dollars per share)		$ 32.20		$ 35.59			$ 34.40
May 2019 Repurchase Program [Member] | Subsequent Event [Member]
Treasury Stock, Shares, Acquired (in shares)	120,000
Treasury Stock, Value, Acquired, Cost Method	$ 2,900
Treasury Stock Acquired, Average Cost Per Share (in dollars per share)	$ 24.19
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 7,800