Note 4 - Loans and Allowance for Loan Losses - Allowance for Loan Losses (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Balance, beginning of period	$ 6,640,000	$ 6,181,000	$ 5,742,449	$ 5,812,000
Provision for loan losses	450,000	200,000	1,500,000	950,000
Losses charged off	(117,000)	(69,000)	(336,000)	(601,000)
Recoveries	36,000	85,000	103,000	236,000
Balance, end of period	7,009,097	6,397,000	7,009,097	6,397,000
Ending balance: individually evaluated for impairment	1,326,000		1,326,000		$ 602,000
Ending balance: collectively evaluated for impairment	5,683,000		5,683,000		5,140,000
Loans:
Ending balance: individually evaluated for impairment	8,863,000		8,863,000		8,699,000
Ending balance: collectively evaluated for impairment	615,729,000		615,729,000		535,699,000
Ending balance: individually evaluated for impairment	1,326,000		1,326,000		602,000
Ending balance: collectively evaluated for impairment	5,683,000		5,683,000		5,140,000
Real Estate, Construction [Member]
Balance, beginning of period	1,739,000	1,668,000	1,377,000	1,246,000
Provision for loan losses	524,000	282,000	847,000	922,000
Losses charged off				(252,000)
Recoveries	16,000	46,000	55,000	80,000
Balance, end of period	2,279,000	1,996,000	2,279,000	1,996,000
Ending balance: individually evaluated for impairment	830,000		830,000		302,000
Ending balance: collectively evaluated for impairment	1,449,000		1,449,000		1,075,000
Loans:
Ending balance: individually evaluated for impairment	5,310,000		5,310,000		5,447,000
Ending balance: collectively evaluated for impairment	56,737,000		56,737,000		35,465,000
Ending balance: individually evaluated for impairment	830,000		830,000		302,000
Ending balance: collectively evaluated for impairment	1,449,000		1,449,000		1,075,000
Commercial Real Estate Portfolio Segment [Member]
Balance, beginning of period	1,954,000	1,613,000	1,687,000	1,526,000
Provision for loan losses	(116,000)	86,000	151,000	141,000
Losses charged off	(71,000)		(71,000)
Recoveries				32,000
Balance, end of period	1,767,000	1,699,000	1,767,000	1,699,000
Ending balance: individually evaluated for impairment
Ending balance: collectively evaluated for impairment	1,767,000		1,767,000		1,687,000
Loans:
Ending balance: individually evaluated for impairment	161,000		161,000		161,000
Ending balance: collectively evaluated for impairment	266,131,000		266,131,000		249,420,000
Ending balance: individually evaluated for impairment
Ending balance: collectively evaluated for impairment	1,767,000		1,767,000		1,687,000
Residential Portfolio Segment [Member] | Real Estate Residential, One To Four Family Units [Member]
Balance, beginning of period	936,000	862,000	856,000	821,000
Provision for loan losses	(81,000)	6,000	2,000	80,000
Losses charged off			(11,000)	(47,000)
Recoveries	1,000	17,000	9,000	31,000
Balance, end of period	856,000	885,000	856,000	885,000
Ending balance: individually evaluated for impairment	56,000		56,000		14,000
Ending balance: collectively evaluated for impairment	800,000		800,000		842,000
Loans:
Ending balance: individually evaluated for impairment	2,274,000		2,274,000		2,060,000
Ending balance: collectively evaluated for impairment	105,477,000		105,477,000		104,351,000
Ending balance: individually evaluated for impairment	56,000		56,000		14,000
Ending balance: collectively evaluated for impairment	800,000		800,000		842,000
Residential Portfolio Segment [Member] | Real Estate Residential, Multi Family Units [Member]
Balance, beginning of period	323,000	157,000	206,000	177,000
Provision for loan losses	52,000	6,000	169,000	(14,000)
Losses charged off	0		0
Recoveries	0		0
Balance, end of period	375,000	163,000	375,000	163,000
Ending balance: individually evaluated for impairment
Ending balance: collectively evaluated for impairment	375,000		375,000		206,000
Loans:
Ending balance: individually evaluated for impairment
Ending balance: collectively evaluated for impairment	74,653,000		74,653,000		48,483,000
Ending balance: individually evaluated for impairment
Ending balance: collectively evaluated for impairment	375,000		375,000		206,000
Commercial Portfolio Segment [Member]
Balance, beginning of period	1,226,000	1,366,000	1,168,000	1,382,000
Provision for loan losses	(99,000)	(40,000)	40,000	102,000
Losses charged off		(11,000)	(85,000)	(170,000)
Recoveries	7,000	8,000	11,000	9,000
Balance, end of period	1,134,000	1,323,000	1,134,000	1,323,000
Ending balance: individually evaluated for impairment	310,000		310,000		241,000
Ending balance: collectively evaluated for impairment	824,000		824,000		927,000
Loans:
Ending balance: individually evaluated for impairment	931,000		931,000		925,000
Ending balance: collectively evaluated for impairment	89,256,000		89,256,000		74,480,000
Ending balance: individually evaluated for impairment	310,000		310,000		241,000
Ending balance: collectively evaluated for impairment	824,000		824,000		927,000
Consumer and Other Loans [Member]
Balance, beginning of period	335,000	288,000	337,000	223,000
Provision for loan losses	126,000	33,000	231,000	102,000
Losses charged off	(46,000)	(58,000)	(169,000)	(132,000)
Recoveries	12,000	14,000	28,000	84,000
Balance, end of period	427,000	277,000	427,000	277,000
Ending balance: individually evaluated for impairment	130,000		130,000		45,000
Ending balance: collectively evaluated for impairment	297,000		297,000		292,000
Loans:
Ending balance: individually evaluated for impairment	187,000		187,000		106,000
Ending balance: collectively evaluated for impairment	23,475,000		23,475,000		23,500,000
Ending balance: individually evaluated for impairment	130,000		130,000		45,000
Ending balance: collectively evaluated for impairment	297,000		297,000		292,000
Unallocated Financing Receivables [Member]
Balance, beginning of period	127,000	227,000	111,000	437,000
Provision for loan losses	44,000	(173,000)	60,000	(383,000)
Losses charged off	0		0
Recoveries	0		0
Balance, end of period	171,000	$ 54,000	171,000	$ 54,000
Ending balance: individually evaluated for impairment
Ending balance: collectively evaluated for impairment	171,000		171,000		111,000
Loans:
Ending balance: individually evaluated for impairment
Ending balance: collectively evaluated for impairment
Ending balance: individually evaluated for impairment
Ending balance: collectively evaluated for impairment	$ 171,000		$ 171,000		$ 111,000