Note 5 - Loans and Allowance for Loan Losses - Allowance for Loan Losses (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Balance, beginning of period	$ 8,049,000	$ 7,847,000	$ 7,607,587	$ 7,996,000
Provision for loan losses	750,000	100,000	1,250,000	100,000
Losses charged off	(51,000)	(373,000)	(145,000)	(661,000)
Recoveries	40,000	97,000	75,000	236,000
Balance, end of period	8,787,917	7,671,000	8,787,917	7,671,000
Ending balance: individually evaluated for impairment	1,319,000		1,319,000		$ 1,094,000
Ending balance: collectively evaluated for impairment	7,467,000		7,467,000		6,514,000
Ending balance: loans acquired with deteriorated credit quality	2,000		2,000		0
Ending balance: individually evaluated for impairment	8,891,000		8,891,000		9,133,000
Ending balance: collectively evaluated for impairment	771,848,000		771,848,000		716,946,000
Ending balance: loans acquired with deteriorated credit quality	2,735,000		2,735,000		2,835,000
Real Estate, Construction [Member]
Balance, beginning of period	1,629,000	1,936,000	1,749,000	2,306,000
Provision for loan losses	(60,000)	212,000	(180,000)	(278,000)
Losses charged off	0	0	0	0
Recoveries	0	21,000	0	141,000
Balance, end of period	1,569,000	2,169,000	1,569,000	2,169,000
Ending balance: individually evaluated for impairment	631,000		631,000		553,000
Ending balance: collectively evaluated for impairment	938,000		938,000		1,196,000
Ending balance: loans acquired with deteriorated credit quality	0		0		0
Ending balance: individually evaluated for impairment	4,443,000		4,443,000		4,742,000
Ending balance: collectively evaluated for impairment	61,911,000		61,911,000		72,567,000
Ending balance: loans acquired with deteriorated credit quality	0		0		0
Commercial Real Estate Portfolio Segment [Member]
Balance, beginning of period	2,577,000	2,137,000
Provision for loan losses	421,000	31,000
Losses charged off	0	0
Recoveries	0	20,000
Balance, end of period	2,998,000	2,188,000	2,998,000	2,188,000
Ending balance: individually evaluated for impairment	96,000		96,000		24,000
Ending balance: collectively evaluated for impairment	2,902,000		2,902,000		2,243,000
Ending balance: loans acquired with deteriorated credit quality	0		0		0
Ending balance: individually evaluated for impairment	1,026,000		1,026,000		650,000
Ending balance: collectively evaluated for impairment	303,250,000		303,250,000		297,318,000
Ending balance: loans acquired with deteriorated credit quality	2,424,000		2,424,000		2,651,000
Commercial Real Estate Portfolio Segment [Member] | Real Estate Loan [Member]
Balance, beginning of period			2,267,000	2,093,000
Provision for loan losses			725,000	75,000
Losses charged off			0	0
Recoveries			6,000	20,000
Balance, end of period	2,998,000	2,188,000	2,998,000	2,188,000
Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Balance, beginning of period	1,154,000	1,386,000	1,001,000	1,297,000
Provision for loan losses	385,000	(168,000)	537,000	(81,000)
Losses charged off	0	(271,000)	0	(271,000)
Recoveries	0	1,000	1,000	3,000
Balance, end of period	1,539,000	948,000	1,539,000	948,000
Ending balance: individually evaluated for impairment	257,000		257,000		197,000
Ending balance: collectively evaluated for impairment	1,282,000		1,282,000		804,000
Ending balance: loans acquired with deteriorated credit quality	0		0		0
Ending balance: individually evaluated for impairment	2,444,000		2,444,000		2,613,000
Ending balance: collectively evaluated for impairment	124,744,000		124,744,000		116,211,000
Ending balance: loans acquired with deteriorated credit quality	0		0		0
Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Balance, beginning of period	755,000	694,000	746,000	641,000
Provision for loan losses	39,000	(21,000)	48,000	32,000
Losses charged off	0	0	0	0
Recoveries	0	0	0	0
Balance, end of period	794,000	673,000	794,000	673,000
Ending balance: individually evaluated for impairment	0		0		0
Ending balance: collectively evaluated for impairment	794,000		794,000		746,000
Ending balance: loans acquired with deteriorated credit quality	0		0		0
Ending balance: individually evaluated for impairment	0		0		0
Ending balance: collectively evaluated for impairment	85,824,000		85,824,000		87,448,000
Ending balance: loans acquired with deteriorated credit quality	0		0		0
Commercial Portfolio Segment [Member]
Balance, beginning of period	1,349,000	974,000	1,129,000	1,160,000
Provision for loan losses	(71,000)	262,000	167,000	301,000
Losses charged off	0	(41,000)	(32,000)	(275,000)
Recoveries	21,000	41,000	35,000	50,000
Balance, end of period	1,299,000	1,236,000	1,299,000	1,236,000
Ending balance: individually evaluated for impairment	319,000		319,000		299,000
Ending balance: collectively evaluated for impairment	978,000		978,000		830,000
Ending balance: loans acquired with deteriorated credit quality	2,000		2,000		0
Ending balance: individually evaluated for impairment	710,000		710,000		908,000
Ending balance: collectively evaluated for impairment	167,358,000		167,358,000		112,956,000
Ending balance: loans acquired with deteriorated credit quality	311,000		311,000		184,000
Consumer and Other Loans [Member]
Ending balance: individually evaluated for impairment	16,000		16,000		21,000
Ending balance: collectively evaluated for impairment	450,000		450,000		422,000
Ending balance: loans acquired with deteriorated credit quality	0		0		0
Ending balance: individually evaluated for impairment	268,000		268,000		220,000
Ending balance: collectively evaluated for impairment	28,761,000		28,761,000		30,446,000
Ending balance: loans acquired with deteriorated credit quality	0		0		0
Consumer Portfolio Segment [Member]
Balance, beginning of period	449,000	368,000	443,000	373,000
Provision for loan losses	49,000	76,000	103,000	117,000
Losses charged off	(51,000)	(61,000)	(113,000)	(115,000)
Recoveries	19,000	14,000	33,000	22,000
Balance, end of period	466,000	397,000	466,000	397,000
Unallocated Financing Receivables [Member]
Balance, beginning of period	136,000	352,000	273,000	126,000
Provision for loan losses	(13,000)	(292,000)	(150,000)	(66,000)
Losses charged off	0	0	0	0
Recoveries	0	0	0	0
Balance, end of period	123,000	$ 60,000	123,000	$ 60,000
Ending balance: individually evaluated for impairment	0		0		0
Ending balance: collectively evaluated for impairment	123,000		123,000		273,000
Ending balance: loans acquired with deteriorated credit quality	0		0		0
Ending balance: individually evaluated for impairment	0		0		0
Ending balance: collectively evaluated for impairment	0		0		0
Ending balance: loans acquired with deteriorated credit quality	$ 0		$ 0		$ 0