Note 11 - Shareholders' Equity (Details Textual)	Dec. 31, 2020 $ / shares shares	Dec. 31, 2019 shares
Preferred Stock, Shares Authorized (in shares)		1,000,000
Common Class A [Member]
Common Stock, Shares Authorized (in shares)	10,000,000	10,000,000
Common Stock, Capital Shares Reserved for Future Issuance (in shares)	1,042,848	1,045,848
Common Stock, Voting Rights, per Share	1
Common Class A [Member] | Minimum [Member]
Dividends Payable, Amount Per Share (in dollars per share) | $ / shares	$ 0.10
Common Class B [Member]
Common Stock, Shares Authorized (in shares)	2,500,000	2,500,000
Common Stock, Voting Rights, per Share	3