Note 14 - Equity Incentive Plan - Stock Options and SAR's Activity (Details)	12 Months Ended
	Dec. 31, 2020 $ / shares shares
Options and SARs outstanding (in shares) | shares	690,968
Options and SAR's outstanding, Weighted Average Exercise Price Per Share (in dollars per share) | $ / shares	$ 41.65
Options and SAR's Granted (in shares) | shares	546,496
Options and SAR's Granted, Weighted Average Exercise Price Per Share (in dollars per share) | $ / shares	$ 37.78
Options and SAR's Cancelled (in shares) | shares	(112,660)
Options and SAR's Cancelled, Weighted Average Exercise Price Per Share (in dollars per share) | $ / shares	$ 50.15
Options and SAR's Expired (in shares) | shares	(104,922)
Options and SAR's Expired, Weighted Average Exercise Price Per Share (in dollars per share) | $ / shares	$ 46.33
Options and SAR's Exercised (in shares) | shares	(123,063)
Options and SAR's Exercised, Weighted Average Exercise Price Per Share (in dollars per share) | $ / shares	$ 12.43
Options and SARs outstanding (in shares) | shares	896,819
Options and SAR's outstanding, Weighted Average Exercise Price Per Share (in dollars per share) | $ / shares	$ 41.50