Note 11 - Earnings Per Common Share - Earnings Per Common Share (Details) - $ / shares	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Basic earnings per share (in shares)	10,971,466	11,025,185
Basic earnings per share (in dollars per share)	$ 1.03	$ 0.77
Effect of dilutive securities - stock options (in shares)	4,711	6,125
Effect of dilutive securities - stock options (in dollars per share)	$ 0	$ 0
Diluted earnings per share (in shares)	10,976,177	11,031,310
Diluted earnings per share (in dollars per share)	$ 1.03	$ 0.77