Note 7 - Fair Value - Carrying Amount and Fair Value of Financial Instruments Included in the Consolidated Balance Sheet (Details) - USD ($)	Mar. 31, 2019	Dec. 31, 2018
Securities available-for-sale, fair value	$ 98,992,000	$ 97,718,000
Securities - equities	17,000	7,000
Fair Value, Inputs, Level 1 [Member]
Securities available-for-sale, fair value	4,472,000	4,445,000
Securities - equities	17,000	7,000
Fair Value, Inputs, Level 2 [Member]
Securities available-for-sale, fair value	91,020,000	89,773,000
Securities - equities
Fair Value, Inputs, Level 3 [Member]
Securities available-for-sale, fair value	3,500,000	3,500,000
Securities - equities
Reported Value Measurement [Member]
Cash and cash equivalents	7,727,000	10,955,000
Interest earning time deposits	6,238,000	6,738,000
Securities available-for-sale, fair value	98,992,000	97,718,000
Securities - equities	17,000	7,000
Loans held for sale	212,000
Loans, net	700,352,000	708,664,000
Federal bank stock	5,799,000	6,351,000
Accrued interest receivable	2,735,000	2,570,000
Total	822,072,000	833,003,000
Deposits	759,427,000	761,546,000
Borrowed funds	35,300,000	45,350,000
Accrued interest payable	603,000	495,000
Total	795,330,000	807,391,000
Estimate of Fair Value Measurement [Member]
Cash and cash equivalents	7,727,000	10,955,000
Interest earning time deposits	6,238,000	6,738,000
Securities available-for-sale, fair value	98,992,000	97,718,000
Securities - equities	17,000	7,000
Loans held for sale	212,000
Loans, net	691,947,000	702,747,000
Federal bank stock
Accrued interest receivable	2,735,000	2,570,000
Total	807,868,000	820,735,000
Deposits	767,115,000	767,009,000
Borrowed funds	34,863,000	44,869,000
Accrued interest payable	603,000	495,000
Total	802,581,000	812,373,000
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member]
Cash and cash equivalents	7,727,000	10,955,000
Interest earning time deposits
Securities available-for-sale, fair value	4,472,000	4,445,000
Securities - equities	17,000	7,000
Loans held for sale
Loans, net
Federal bank stock
Accrued interest receivable	100,000	63,000
Total	12,316,000	15,470,000
Deposits	540,936,000	539,946,000
Borrowed funds
Accrued interest payable	46,000	30,000
Total	540,982,000	539,976,000
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member]
Cash and cash equivalents
Interest earning time deposits	6,238,000	6,738,000
Securities available-for-sale, fair value	91,020,000	89,773,000
Securities - equities
Loans held for sale	212,000
Loans, net
Federal bank stock
Accrued interest receivable	349,000	351,000
Total	97,819,000	96,862,000
Deposits	226,179,000	227,063,000
Borrowed funds	34,863,000	44,869,000
Accrued interest payable	557,000	465,000
Total	261,599,000	272,397,000
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 3 [Member]
Cash and cash equivalents
Interest earning time deposits
Securities available-for-sale, fair value	3,500,000	3,500,000
Securities - equities
Loans held for sale
Loans, net	691,947,000	702,747,000
Federal bank stock
Accrued interest receivable	2,286,000	2,156,000
Total	697,733,000	708,403,000
Deposits
Borrowed funds
Accrued interest payable
Total