Note 10 - Stock Based Compensation - Nonvested Restricted Stock Activity (Details) - Restricted Stock [Member]	9 Months Ended
	Sep. 30, 2021 $ / shares shares
Nonvested, shares (in shares) | shares	58,539
Nonvested, weighted average grant date value per share (in dollars per share) | $ / shares	$ 34.81
Granted, shares (in shares) | shares	24,709
Granted, weighted average grant date value per share (in dollars per share) | $ / shares	$ 28.26
Vested, shares (in shares) | shares	(16,661)
Vested, weighted average grant date value per share (in dollars per share) | $ / shares	$ 38.63
Forfeited, shares (in shares) | shares	(2,065)
Forfeited, weighted average grant date value per share (in dollars per share) | $ / shares	$ 30.72
Nonvested, shares (in shares) | shares	64,522
Nonvested, weighted average grant date value per share (in dollars per share) | $ / shares	$ 31.45