Note 9 - Benefit Plans - Performance Stock Units (Details) - Performance Shares [Member]	3 Months Ended
	Mar. 31, 2021 $ / shares shares
Balance of shares non-vested (in shares) | shares	53,075
Balance of shares non-vested, weighted average grant-date price (in dollars per share) | $ / shares	$ 15.40
Granted (in shares) | shares	0
Granted (in dollars per share) | $ / shares	$ 0
Vested (in shares) | shares	0
Vested, weighted average grant-date price (in dollars per share) | $ / shares	$ 0
Forfeited (in shares) | shares	0
Forfeited, weighted average grant-date price (in dollars per share) | $ / shares	$ 0
Balance of shares non-vested (in shares) | shares	53,075
Balance of shares non-vested, weighted average grant-date price (in dollars per share) | $ / shares	$ 15.40