Note 16 - Stock-Based Compensation - Stock Option Plans (Details) - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Stock-Based Compensation
Outstanding, shares (in shares)	407,763	426,913	469,572
Outstanding, Weighted average exercise price (in dollars per share)	$ 22.24	$ 20.14	$ 18.52
Granted, shares (in shares)	22,150	23,350	20,200
Granted, Weighted average exercise price (in dollars per share)	$ 43.61	$ 39.12	$ 36.00
Exercised, shares (in shares)	(60,317)	(41,650)	(59,393)
Exercised, Weighted average exercise price (in dollars per share)	$ 15.76	$ 10.67	$ 12.11
Forfeited, shares (in shares)	(1,598)	(850)	(3,466)
Forfeited, Weighted average exercise price (in dollars per share)	$ 38.50	$ 19.94	$ 31.59
Outstanding, shares (in shares)	367,998	407,763	426,913
Outstanding, Weighted average exercise price (in dollars per share)	$ 24.46	$ 22.24	$ 20.14
Exercisable, , shares (in shares)	318,266	354,899	365,084
Weighted-average grant date fair value (in dollars per share)	$ 10.85	$ 10.07	$ 11.29