Note 7 - Subordinated Debt (Details Textual) - USD ($)	1 Months Ended
	Jul. 31, 2007	Sep. 30, 2020	Dec. 31, 2019
Trust Common Securities [Member]
Investment in Securities	$ 155,000
Trust Formed by Company [Member]
Floating Rate Trust Preferred Securities, Issued During Period	$ 5,000,000.0
Securities, Interest Rate, Effective Percentage		1.70%	3.34%
Trust Formed by Company [Member] | London Interbank Offered Rate (LIBOR) [Member]
Securities, Basis Spread on Variable Rate	1.45%