Note 1 - Basis of Presentation - Performance Based Restricted Stock Activity (Details) - Performance Shares [Member] shares in Thousands	6 Months Ended
	Jun. 30, 2021 $ / shares shares
Unvested (in shares) | shares	44
Unvested, weighted average grant date fair value (in dollars per share) | $ / shares	$ 33.73
Expired (in shares) | shares	(15)
Expired, weighted average option exercise price per share (in dollars per share) | $ / shares	$ 47.40
Unvested (in shares) | shares	29
Unvested, weighted average grant date fair value (in dollars per share) | $ / shares	$ 26.80