Note 5 - Loans and Allowance for Loan Losses - Allowance for Loan Losses (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Balance, beginning of period	$ 7,671,000	$ 7,573,000	$ 7,995,569	$ 7,107,000
Provision for loan losses	100,000	200,000	200,000	925,000
Losses charged off	(313,000)	(91,000)	(973,000)	(414,000)
Recoveries	99,000	50,000	334,000	114,000
Balance, end of period	7,557,311	7,732,000	7,557,311	7,732,000
Ending balance: individually evaluated for impairment	1,014,000		1,014,000		$ 1,612,000
Ending balance: collectively evaluated for impairment	6,540,000		6,540,000		6,384,000
Ending balance: loans acquired with deteriorated credit quality	3,000		3,000
Ending balance: individually evaluated for impairment	13,108,000		13,108,000		17,379,000
Ending balance: collectively evaluated for impairment	736,089,000		736,089,000		766,343,000
Ending balance: loans acquired with deteriorated credit quality	3,028,000		3,028,000		3,173,000
Real Estate, Construction [Member]
Balance, beginning of period	2,169,000	2,484,000	2,306,000	2,244,000
Provision for loan losses	(245,000)	(219,000)	(523,000)	(13,000)
Losses charged off
Recoveries	28,000	36,000	169,000	70,000
Balance, end of period	1,952,000	2,301,000	1,952,000	2,301,000
Ending balance: individually evaluated for impairment	554,000		554,000		552,000
Ending balance: collectively evaluated for impairment	1,398,000		1,398,000		1,754,000
Ending balance: loans acquired with deteriorated credit quality
Ending balance: individually evaluated for impairment	3,816,000		3,816,000		4,088,000
Ending balance: collectively evaluated for impairment	84,359,000		84,359,000		84,507,000
Ending balance: loans acquired with deteriorated credit quality
Commercial Real Estate Portfolio Segment [Member]
Balance, beginning of period	2,188,000	1,787,000
Provision for loan losses	242,000	158,000
Losses charged off	(122,000)
Recoveries	1,000
Balance, end of period	2,309,000	1,945,000	2,309,000	1,945,000
Ending balance: individually evaluated for impairment	24,000		24,000		106,000
Ending balance: collectively evaluated for impairment	2,285,000		2,285,000		1,987,000
Ending balance: loans acquired with deteriorated credit quality
Ending balance: individually evaluated for impairment	412,000		412,000		1,588,000
Ending balance: collectively evaluated for impairment	305,188,000		305,188,000		317,488,000
Ending balance: loans acquired with deteriorated credit quality	2,671,000		2,671,000		2,782,000
Commercial Real Estate Portfolio Segment [Member] | Real Estate Loan [Member]
Balance, beginning of period			2,093,000	1,789,000
Provision for loan losses			317,000	155,000
Losses charged off			(122,000)
Recoveries			21,000	1,000
Balance, end of period	2,309,000	1,945,000	2,309,000	1,945,000
Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Balance, beginning of period	948,000	1,237,000	1,297,000	946,000
Provision for loan losses	42,000	96,000	(41,000)	386,000
Losses charged off		(3,000)	(271,000)	(3,000)
Recoveries	1,000	1,000	6,000	2,000
Balance, end of period	991,000	1,331,000	991,000	1,331,000
Ending balance: individually evaluated for impairment	202,000		202,000		573,000
Ending balance: collectively evaluated for impairment	789,000		789,000		724,000
Ending balance: loans acquired with deteriorated credit quality
Ending balance: individually evaluated for impairment	2,166,000		2,166,000		4,520,000
Ending balance: collectively evaluated for impairment	119,524,000		119,524,000		128,258,000
Ending balance: loans acquired with deteriorated credit quality
Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Balance, beginning of period	673,000	553,000	641,000	464,000
Provision for loan losses	50,000	97,000	82,000	186,000
Losses charged off	0	0	0	0
Recoveries	0	0	0	0
Balance, end of period	723,000	650,000	723,000	650,000
Ending balance: individually evaluated for impairment
Ending balance: collectively evaluated for impairment	723,000		723,000		641,000
Ending balance: loans acquired with deteriorated credit quality
Ending balance: individually evaluated for impairment	5,930,000		5,930,000		5,952,000
Ending balance: collectively evaluated for impairment	87,699,000		87,699,000		84,663,000
Ending balance: loans acquired with deteriorated credit quality
Commercial Portfolio Segment [Member]
Balance, beginning of period	1,236,000	1,085,000	1,160,000	1,031,000
Provision for loan losses	(125,000)	(44,000)	175,000	98,000
Losses charged off	(106,000)	(14,000)	(381,000)	(110,000)
Recoveries	55,000	4,000	106,000	12,000
Balance, end of period	1,060,000	1,031,000	1,060,000	1,031,000
Ending balance: individually evaluated for impairment	214,000		214,000		363,000
Ending balance: collectively evaluated for impairment	846,000		846,000		797,000
Ending balance: loans acquired with deteriorated credit quality
Ending balance: individually evaluated for impairment	599,000		599,000		1,062,000
Ending balance: collectively evaluated for impairment	108,072,000		108,072,000		118,459,000
Ending balance: loans acquired with deteriorated credit quality	67,000		67,000		216,000
Consumer Portfolio Segment [Member]
Balance, beginning of period	397,000	367,000	373,000	454,000
Provision for loan losses	99,000	65,000	219,000	185,000
Losses charged off	(85,000)	(74,000)	(199,000)	(301,000)
Recoveries	14,000	9,000	32,000	29,000
Balance, end of period	425,000	367,000	425,000	367,000
Consumer and Other Loans [Member]
Ending balance: individually evaluated for impairment	20,000		20,000		18,000
Ending balance: collectively evaluated for impairment	402,000		402,000		355,000
Ending balance: loans acquired with deteriorated credit quality	3,000		3,000
Ending balance: individually evaluated for impairment	185,000		185,000		169,000
Ending balance: collectively evaluated for impairment	31,247,000		31,247,000		32,968,000
Ending balance: loans acquired with deteriorated credit quality	290,000		290,000		175,000
Unallocated Financing Receivables [Member]
Balance, beginning of period	60,000	60,000	126,000	179,000
Provision for loan losses	37,000	47,000	(29,000)	(72,000)
Losses charged off	0	0	0	0
Recoveries	0	0	0	0
Balance, end of period	97,000	$ 107,000	97,000	$ 107,000
Ending balance: individually evaluated for impairment
Ending balance: collectively evaluated for impairment	97,000		97,000		126,000
Ending balance: loans acquired with deteriorated credit quality
Ending balance: individually evaluated for impairment
Ending balance: collectively evaluated for impairment
Ending balance: loans acquired with deteriorated credit quality