Note 5 - Loans and Allowance for Loan Losses - Allowance for Loan Losses (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Balance	$ 7,103,000	$ 6,172,000	$ 7,107,418	$ 5,742,000
Provision for loan losses	500,000	575,000	725,000	1,050,000
Losses charged off	(59,000)	(138,000)	(322,000)	(219,000)
Recoveries	29,000	31,000	63,000	67,000
Balance	7,572,510	6,640,000	7,572,510	6,640,000
Ending balance: individually evaluated for impairment	1,287,000		1,287,000		$ 1,249,000
Ending balance: collectively evaluated for impairment	6,286,000		6,286,000		5,858,000
Ending balance: loans acquired with deteriorated credit quality
Ending balance: individually evaluated for impairment	9,518,000		9,518,000		10,827,000
Ending balance: collectively evaluated for impairment	765,333,000		765,333,000		626,548,000
Ending balance: loans acquired with deteriorated credit quality	5,965,000		5,965,000
Real Estate, Construction [Member]
Balance	2,223,000	1,643,000	2,244,000	1,377,000
Provision for loan losses	248,000	75,000	208,000	323,000
Losses charged off
Recoveries	13,000	21,000	32,000	39,000
Balance	2,484,000	1,739,000	2,484,000	1,739,000
Ending balance: individually evaluated for impairment	738,000		738,000		738,000
Ending balance: collectively evaluated for impairment	1,746,000		1,746,000		1,506,000
Ending balance: loans acquired with deteriorated credit quality
Ending balance: individually evaluated for impairment	4,298,000		4,298,000		4,452,000
Ending balance: collectively evaluated for impairment	101,677,000		101,677,000		60,292,000
Ending balance: loans acquired with deteriorated credit quality
Commercial Real Estate Portfolio Segment [Member]
Balance	1,876,000
Provision for loan losses	(90,000)
Losses charged off
Recoveries	1,000
Balance	1,787,000		1,787,000
Ending balance: individually evaluated for impairment
Ending balance: collectively evaluated for impairment	1,787,000		1,787,000		1,789,000
Ending balance: loans acquired with deteriorated credit quality
Ending balance: individually evaluated for impairment	161,000		161,000		161,000
Ending balance: collectively evaluated for impairment	295,782,000		295,782,000		261,705,000
Ending balance: loans acquired with deteriorated credit quality	4,383,000		4,383,000
Commercial Real Estate Portfolio Segment [Member] | Real Estate Loan [Member]
Balance		1,742,000	1,789,000	1,687,000
Provision for loan losses		212,000	(3,000)	267,000
Losses charged off
Recoveries			1,000
Balance	1,787,000	1,954,000	1,787,000	1,954,000
Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Balance	1,113,000	825,000	946,000	856,000
Provision for loan losses	123,000	109,000	290,000	83,000
Losses charged off				(11,000)
Recoveries	1,000	2,000	1,000	8,000
Balance	1,237,000	936,000	1,237,000	936,000
Ending balance: individually evaluated for impairment	322,000		322,000		127,000
Ending balance: collectively evaluated for impairment	915,000		915,000		819,000
Ending balance: loans acquired with deteriorated credit quality
Ending balance: individually evaluated for impairment	4,396,000		4,396,000		4,424,000
Ending balance: collectively evaluated for impairment	131,043,000		131,043,000		101,877,000
Ending balance: loans acquired with deteriorated credit quality
Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Balance	487,000	273,000	464,000	206,000
Provision for loan losses	66,000	50,000	89,000	117,000
Losses charged off	0	0	0	0
Recoveries	0	0	0	0
Balance	553,000	323,000	553,000	323,000
Ending balance: individually evaluated for impairment
Ending balance: collectively evaluated for impairment	553,000		553,000		464,000
Ending balance: loans acquired with deteriorated credit quality
Ending balance: individually evaluated for impairment					775,000
Ending balance: collectively evaluated for impairment	83,204,000		83,204,000		84,450,000
Ending balance: loans acquired with deteriorated credit quality
Commercial Portfolio Segment [Member]
Balance	958,000	1,354,000	1,031,000	1,168,000
Provision for loan losses	122,000	(45,000)	142,000	139,000
Losses charged off		(85,000)	(96,000)	(85,000)
Recoveries	5,000	2,000	8,000	4,000
Balance	1,085,000	1,226,000	1,085,000	1,226,000
Ending balance: individually evaluated for impairment	213,000		213,000		246,000
Ending balance: collectively evaluated for impairment	872,000		872,000		785,000
Ending balance: loans acquired with deteriorated credit quality
Ending balance: individually evaluated for impairment	574,000		574,000		739,000
Ending balance: collectively evaluated for impairment	118,337,000		118,337,000		93,784,000
Ending balance: loans acquired with deteriorated credit quality	1,381,000		1,381,000
Consumer and Other Loans [Member]
Balance	291,000	293,000	454,000	337,000
Provision for loan losses	126,000	89,000	118,000	105,000
Losses charged off	(59,000)	(53,000)	(226,000)	(123,000)
Recoveries	9,000	6,000	21,000	16,000
Balance	367,000	335,000	367,000	335,000
Ending balance: individually evaluated for impairment	14,000		14,000		138,000
Ending balance: collectively evaluated for impairment	353,000		353,000		316,000
Ending balance: loans acquired with deteriorated credit quality
Ending balance: individually evaluated for impairment	89,000		89,000		276,000
Ending balance: collectively evaluated for impairment	35,290,000		35,290,000		24,440,000
Ending balance: loans acquired with deteriorated credit quality	201,000		201,000
Unallocated Financing Receivables [Member]
Balance	155,000
Provision for loan losses	(95,000)
Losses charged off	0
Recoveries	0
Balance	60,000		60,000
Ending balance: individually evaluated for impairment
Ending balance: collectively evaluated for impairment	60,000		60,000		179,000
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
Unallocated [Member]
Balance		42,000	179,000	111,000
Provision for loan losses		85,000	(119,000)	16,000
Losses charged off		0	0	0
Recoveries		0	0	0
Balance	$ 60,000	$ 127,000	$ 60,000	$ 127,000