Note 15 - Stock Compensation - Summary of the Status of the Stock Option Plan (Details) - $ / shares				12 Months Ended
	Oct. 01, 2018	Jan. 01, 2018	Mar. 03, 2017	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Balance, vested (in shares)				25,300	16,400
Balance, weighted average exercise price per share (in dollars per share)				$ 28.40	$ 28.34
Balance, non-vested shares (in shares)				19,700	28,600
Balance, weighted average exercise price per share, non-vested (in dollars per share)				$ 28.71	$ 28.65
Balance (in shares)				45,000	45,000
Balance, weighted average exercise price (in dollars per share)				$ 28.54	$ 28.54
Granted, non-vested shares (in shares)	5,000	7,000	35,000	0	0	0
Granted, weighted average exercise price per share, non-vested (in dollars per share)				$ 0
Forfeited, non-vested shares (in shares)				0	0
Forfeited, weighted average exercise price per share, non-vested (in dollars per share)				$ 0	$ 0
Vested, vested (in shares)				8,900	8,900
Vested, weighted average exercise price per share (in dollars per share)				$ 28.52	$ 28.52
Vested, non-vested shares (in shares)				(8,900)	(8,900)
Vested, weighted average exercise price per share, non-vested (in dollars per share)				$ 28.52	$ 28.52
Balance, vested (in shares)				34,200	25,300	16,400
Balance, weighted average exercise price per share (in dollars per share)				$ 28.43	$ 28.40	$ 28.34
Balance, non-vested shares (in shares)				10,800	19,700	28,600
Balance, weighted average exercise price per share, non-vested (in dollars per share)				$ 28.86	$ 28.71	$ 28.65
Balance (in shares)				45,000	45,000	45,000
Balance, weighted average exercise price (in dollars per share)				$ 28.54	$ 28.54	$ 28.54
Remaining contractual life (years), vested (Year)				1 year 2 months 12 days	2 years 2 months 12 days
Remaining contractual life (years), non-vested shares (Year)				1 year 4 months 24 days	2 years 3 months 18 days
Remaining contractual life (years), outstanding shares (Year)				1 year 3 months 18 days	2 years 3 months 18 days
Options exercisable at year end, weighted average exercise price per share, vested (in dollars per share)					$ 0