Note 4 - Loans and Allowance for Loan Losses - Allowance for Loan Losses (Details) - USD ($)	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Balance, beginning of year				$ 7,607,587				$ 7,996,000	$ 7,607,587	$ 7,996,000	$ 7,107,000
Provision for Loan Losses	$ 1,400,000	$ 950,000	$ 750,000	500,000	$ 0	$ 100,000	$ 100,000	0	3,600,000	200,000	1,225,000
Losses charged off									(1,710,000)	(1,055,000)	(537,000)
Recoveries									119,000	467,000	201,000
Balance, end of year	9,617,024				7,607,587				9,617,024	7,607,587	7,996,000
Ending balance: individually evaluated for impairment	420,000				1,094,000				420,000	1,094,000	1,612,000
Ending balance: collectively evaluated for impairment	9,196,000				6,514,000				9,196,000	6,514,000	6,384,000
Ending balance: loans acquired with deteriorated credit quality	1,000				0				1,000	0	0
Ending balance: individually evaluated for impairment	16,472,000				9,133,000				16,472,000	9,133,000	17,379,000
Ending balance: collectively evaluated for impairment	734,394,000				716,946,000				734,394,000	716,946,000	766,343,000
Carrying amount, net of fair value adjustment	2,542,000				2,835,000				2,542,000	2,835,000	3,173,000
Real Estate, Construction [Member]
Balance, beginning of year				1,749,000				2,306,000	1,749,000	2,306,000	2,244,000
Provision for Loan Losses									121,000	(809,000)	(35,000)
Losses charged off									(738,000)	0	0
Recoveries									0	252,000	97,000
Balance, end of year	1,132,000				1,749,000				1,132,000	1,749,000	2,306,000
Ending balance: individually evaluated for impairment	114,000				553,000				114,000	553,000	552,000
Ending balance: collectively evaluated for impairment	1,018,000				1,196,000				1,018,000	1,196,000	1,754,000
Ending balance: loans acquired with deteriorated credit quality	0				0				0	0	0
Ending balance: individually evaluated for impairment	6,239,000				4,742,000				6,239,000	4,742,000	4,088,000
Ending balance: collectively evaluated for impairment	64,608,000				72,567,000				64,608,000	72,567,000	84,507,000
Carrying amount, net of fair value adjustment	0				0				0	0	0
Commercial Real Estate Portfolio Segment [Member]
Balance, beginning of year				2,267,000				2,093,000	2,267,000	2,093,000	1,789,000
Provision for Loan Losses									1,350,000	265,000	339,000
Losses charged off									0	(122,000)	(37,000)
Recoveries									7,000	31,000	2,000
Balance, end of year	3,624,000				2,267,000				3,624,000	2,267,000	2,093,000
Ending balance: individually evaluated for impairment	117,000				24,000				117,000	24,000	106,000
Ending balance: collectively evaluated for impairment	3,507,000				2,243,000				3,507,000	2,243,000	1,987,000
Ending balance: loans acquired with deteriorated credit quality	0				0				0	0	0
Ending balance: individually evaluated for impairment	1,810,000				650,000				1,810,000	650,000	1,588,000
Ending balance: collectively evaluated for impairment	301,453,000				297,318,000				301,453,000	297,318,000	317,488,000
Carrying amount, net of fair value adjustment	2,410,000				2,651,000				2,410,000	2,651,000	2,782,000
Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Balance, beginning of year				1,001,000				1,297,000	1,001,000	1,297,000	946,000
Provision for Loan Losses									440,000	(32,000)	327,000
Losses charged off									(2,000)	(272,000)	(8,000)
Recoveries									6,000	8,000	32,000
Balance, end of year	1,445,000				1,001,000				1,445,000	1,001,000	1,297,000
Ending balance: individually evaluated for impairment	112,000				197,000				112,000	197,000	573,000
Ending balance: collectively evaluated for impairment	1,333,000				804,000				1,333,000	804,000	724,000
Ending balance: loans acquired with deteriorated credit quality	0				0				0	0	0
Ending balance: individually evaluated for impairment	3,110,000				2,613,000				3,110,000	2,613,000	4,520,000
Ending balance: collectively evaluated for impairment	112,689,000				116,211,000				112,689,000	116,211,000	128,258,000
Carrying amount, net of fair value adjustment	0				0				0	0	0
Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Balance, beginning of year				746,000				641,000	746,000	641,000	464,000
Provision for Loan Losses									312,000	105,000	177,000
Losses charged off									0	0	0
Recoveries									0	0	0
Balance, end of year	1,058,000				746,000				1,058,000	746,000	641,000
Ending balance: individually evaluated for impairment	0				0				0	0	0
Ending balance: collectively evaluated for impairment	1,058,000				746,000				1,058,000	746,000	641,000
Ending balance: loans acquired with deteriorated credit quality	0				0				0	0	0
Ending balance: individually evaluated for impairment	0				0				0	0	5,952,000
Ending balance: collectively evaluated for impairment	90,029,000				87,448,000				90,029,000	87,448,000	84,663,000
Carrying amount, net of fair value adjustment	0				0				0	0	0
Commercial Portfolio Segment [Member]
Balance, beginning of year				1,129,000				1,160,000	1,129,000	1,160,000	1,031,000
Provision for Loan Losses									669,000	225,000	222,000
Losses charged off									(709,000)	(381,000)	(110,000)
Recoveries									40,000	125,000	17,000
Balance, end of year	1,129,000				1,129,000				1,129,000	1,129,000	1,160,000
Ending balance: individually evaluated for impairment	62,000				299,000				62,000	299,000	363,000
Ending balance: collectively evaluated for impairment	1,066,000				830,000				1,066,000	830,000	797,000
Ending balance: loans acquired with deteriorated credit quality	1,000				0				1,000	0	0
Ending balance: individually evaluated for impairment	5,111,000				908,000				5,111,000	908,000	1,062,000
Ending balance: collectively evaluated for impairment	139,083,000				112,956,000				139,083,000	112,956,000	118,459,000
Carrying amount, net of fair value adjustment	132,000				184,000				132,000	184,000	216,000
Consumer Portfolio Segment [Member]
Balance, beginning of year				443,000				373,000	443,000	373,000	454,000
Provision for Loan Losses									323,000	299,000	248,000
Losses charged off									(261,000)	(280,000)	(382,000)
Recoveries									66,000	51,000	53,000
Balance, end of year	571,000				443,000				571,000	443,000	373,000
Ending balance: individually evaluated for impairment	15,000				21,000				15,000	21,000	18,000
Ending balance: collectively evaluated for impairment	556,000				422,000				556,000	422,000	355,000
Ending balance: loans acquired with deteriorated credit quality	0				0				0	0	0
Ending balance: individually evaluated for impairment	202,000				220,000				202,000	220,000	169,000
Ending balance: collectively evaluated for impairment	26,532,000				30,446,000				26,532,000	30,446,000	32,968,000
Carrying amount, net of fair value adjustment	0				0				0	0	175,000
Unallocated Financing Receivables [Member]
Balance, beginning of year				$ 273,000				$ 126,000	273,000	126,000	179,000
Provision for Loan Losses									385,000	147,000	(53,000)
Losses charged off									0	0	0
Recoveries									0	0	0
Balance, end of year	658,000				273,000				658,000	273,000	126,000
Ending balance: individually evaluated for impairment	0				0				0	0	0
Ending balance: collectively evaluated for impairment	658,000				273,000				658,000	273,000	126,000
Ending balance: loans acquired with deteriorated credit quality	0				0				0	0	0
Ending balance: individually evaluated for impairment	0				0				0	0	0
Ending balance: collectively evaluated for impairment	0				0				0	0	0
Carrying amount, net of fair value adjustment	$ 0				$ 0				$ 0	$ 0	$ 0