Note 7 - Fair Value - Carrying Amount and Fair Value of Financial Instruments Included in the Consolidated Balance Sheet (Details) - USD ($)	Mar. 31, 2020	Dec. 31, 2019
Debt securities, fair value	$ 114,419,000	$ 120,107,000
Securities - equities	9,000	19,000
Federal bank stock	6,866,000	5,790,000
Fair Value, Inputs, Level 1 [Member]
Debt securities, fair value
Securities - equities	9,000	19,000
Fair Value, Inputs, Level 2 [Member]
Debt securities, fair value	110,397,000	116,085,000
Securities - equities
Fair Value, Inputs, Level 3 [Member]
Debt securities, fair value	4,022,000	4,022,000
Securities - equities
Reported Value Measurement [Member]
Cash and cash equivalents	10,089,000	14,986,000
Interest earning time deposits	8,948,000	9,698,000
Debt securities, fair value	114,419,000	120,107,000
Securities - equities	9,000	19,000
Loans, net	734,730,000	695,348,000
Federal bank stock	6,866,000	5,790,000
Accrued interest receivable	2,861,000	2,600,000
Total	877,922,000	848,548,000
Deposits	782,716,000	787,124,000
Borrowed funds	60,550,000	28,550,000
Accrued interest payable	661,000	616,000
Total	843,927,000	816,290,000
Estimate of Fair Value Measurement [Member]
Cash and cash equivalents	10,089,000	14,986,000
Interest earning time deposits	8,948,000	9,698,000
Debt securities, fair value	114,419,000	120,107,000
Securities - equities	9,000	19,000
Loans, net	730,472,000	697,990,000
Federal bank stock
Accrued interest receivable	2,861,000	2,600,000
Total	866,798,000	845,400,000
Deposits	788,806,000	793,999,000
Borrowed funds	52,678,000	29,133,000
Accrued interest payable	661,000	616,000
Total	842,145,000	823,748,000
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member]
Cash and cash equivalents	10,089,000	14,986,000
Interest earning time deposits
Debt securities, fair value
Securities - equities	9,000	19,000
Loans, net
Federal bank stock
Accrued interest receivable	114,000	78,000
Total	10,212,000	15,083,000
Deposits	570,399,000	569,357,000
Borrowed funds
Accrued interest payable	57,000	51,000
Total	570,456,000	569,408,000
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member]
Cash and cash equivalents
Interest earning time deposits	8,948,000	9,698,000
Debt securities, fair value	110,397,000	116,085,000
Securities - equities
Loans, net
Accrued interest receivable	476,000	419,000
Total	119,821,000	126,202,000
Deposits	218,407,000	224,642,000
Borrowed funds	52,678,000	29,133,000
Accrued interest payable	604,000	565,000
Total	271,689,000	254,340,000
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member]
Cash and cash equivalents
Interest earning time deposits
Debt securities, fair value	4,022,000	4,022,000
Securities - equities
Loans, net	730,472,000	697,990,000
Federal bank stock
Accrued interest receivable	2,271,000	2,103,000
Total	736,765,000	704,115,000
Deposits
Borrowed funds
Accrued interest payable
Total