Note 5 - Loans and the Allowance for Loan Losses - Allowance for Loan Losses (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Balance, beginning of year	$ 6,958,000	$ 6,669,000	$ 6,549,000
Provision charged to operations	1,500,000	1,000,000	600,000
Losses charged to allowance	(1,521,000)	(1,191,000)	(879,000)
Recoveries	306,000	480,000	399,000
Balance, end of year	$ 7,243,000	$ 6,958,000	$ 6,669,000