Note 7 - Share-based Compensation - Restricted Stock Transactions (Details) - Restricted Stock [Member]	3 Months Ended
	Mar. 31, 2022 $ / shares shares
Outstanding (in shares) | shares	458,166
Outstanding, weighted average grant date fair value (in dollars per share) | $ / shares	$ 19.51
Granted (in shares) | shares	23,677
Granted, weighted average grant date fair value (in dollars per share) | $ / shares	$ 20.52
Vested (in shares) | shares	(55,039)
Vested, weighted average grant date fair value (in dollars per share) | $ / shares	$ 19.50
Outstanding (in shares) | shares	426,804
Outstanding, weighted average grant date fair value (in dollars per share) | $ / shares	$ 19.57