Note 5 - Equity (Details Textual) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	Oct. 31, 2021	Dec. 31, 2021	Dec. 31, 2020	May 31, 2021	Jul. 31, 2015
Treasury Stock, Value, Acquired, Cost Method		$ 40,655
Share Repurchase Program Authorized in July 2015 [Member]
Stock Repurchase Program, Authorized Amount					$ 25,000
Treasury Stock, Shares, Acquired (in shares)		0	0
Share Repurchase Program Authorized in May 2021 [Member]
Stock Repurchase Program, Authorized Amount				$ 6,000
Treasury Stock, Shares, Acquired (in shares)		236,159
Treasury Stock, Value, Acquired, Cost Method		$ 1,600
Treasury Stock Acquired, Average Cost Per Share (in dollars per share)		$ 6.94
Dutch Auction Self-tender [Member]
Treasury Stock, Shares, Acquired (in shares)	4,300,000
Treasury Stock, Value, Acquired, Cost Method	$ 39,000
Treasury Stock Acquired, Average Cost Per Share (in dollars per share)	$ 9.06
Treasury Stock, Transaction Costs	$ 300