Note 14 - Stock-based Compensation - Options Outstanding by Exercise Price Range (Details)	3 Months Ended
	Mar. 31, 2022 $ / shares shares
Options outstanding (in shares) | shares	467,326
Exercise price, upper range (in dollars per share)
Weighted average exercise price (in dollars per share)	$ 66.88
Weighted average remaining contractual life (Year)	3 years 6 months
Exercise Price Range 1 [Member]
Exercise price, lower range (in dollars per share)	$ 61.90
Options outstanding (in shares) | shares	332,620
Exercise price, upper range (in dollars per share)	$ 68.84
Weighted average exercise price (in dollars per share)	$ 63.96
Weighted average remaining contractual life (Year)	4 years 1 month 6 days
Exercise Price Range 2 [Member]
Exercise price, lower range (in dollars per share)	$ 71.64
Options outstanding (in shares) | shares	134,706
Exercise price, upper range (in dollars per share)	$ 77.92
Weighted average exercise price (in dollars per share)	$ 74.11
Weighted average remaining contractual life (Year)	2 years 1 month 6 days