Note 3 - Loans and Allowance for Loan Losses - Activity for Troubled Debt Restructurings (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Commercial and Industrial [Member]
Beginning Balance	$ 2,425,000	$ 2,775,000	$ 2,989,000	$ 1,503,000
Charge-Offs	0	0	(230,000)	0
Payments	0	(572,000)	(934,000)	(1,950,000)
Transfers to ORE	0	0	0	0
Net Additions/Deletions	3,315,000	858,000	3,915,000	3,508,000
Ending Balance	5,740,000	3,061,000	5,740,000	3,061,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Beginning Balance	229,000	934,000	383,000	1,488,000
Charge-Offs	0	0	0	0
Payments	(207,000)	(276,000)	(361,000)	(830,000)
Transfers to ORE	0	0	0	0
Net Additions/Deletions	0	0	0	0
Ending Balance	22,000	658,000	22,000	658,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Owner Occupied Loan [Member]
Beginning Balance	1,784,000	1,658,000	1,599,000	906,000
Charge-Offs	0	0	0	0
Payments	(439,000)	(144,000)	(4,057,000)	(196,000)
Transfers to ORE	0	0	0	0
Net Additions/Deletions	2,278,000	477,000	6,081,000	1,281,000
Ending Balance	3,623,000	1,991,000	3,623,000	1,991,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Non Owner Occupied Loan [Member]
Beginning Balance	0	564,000	0	5,110,000
Charge-Offs	0	0	0	0
Payments	0	(24,000)	0	(167,000)
Transfers to ORE	0	0	0	0
Net Additions/Deletions	0	0	0	(4,403,000)
Ending Balance	0	540,000	0	540,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Beginning Balance	0	131,000	0	716,000
Charge-Offs	0	0	0	0
Payments	0	(131,000)	0	(404,000)
Transfers to ORE	0	0	0	0
Net Additions/Deletions	0	0	0	(312,000)
Ending Balance	0	0	0	0
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Commercial and Industrial [Member]
Beginning Balance	694,000	992,000	1,001,000	1,125,000
Charge-Offs	0	0	(275,000)	0
Payments	(36,000)	(239,000)	(69,000)	(518,000)
Transfers to ORE	0	0	0	0
Net Additions/Deletions	(80,000)	280,000	(79,000)	426,000
Ending Balance	578,000	1,033,000	578,000	1,033,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Beginning Balance	0	33,000	0	0
Charge-Offs	0	0	0	0
Payments	0	(4,000)	0	(4,000)
Transfers to ORE	0	0	0	0
Net Additions/Deletions	0	0	0	33,000
Ending Balance	0	29,000	0	29,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Owner Occupied Loan [Member]
Beginning Balance	393,000	980,000	427,000	900,000
Charge-Offs	0	(227,000)	0	(239,000)
Payments	(15,000)	(253,000)	(1,645,000)	(161,000)
Transfers to ORE	(93,000)	0	(92,000)	0
Net Additions/Deletions	151,000	0	1,746,000	0
Ending Balance	436,000	500,000	436,000	500,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Non Owner Occupied Loan [Member]
Beginning Balance	225,000	914,000	237,000	728,000
Charge-Offs	0	0	0	0
Payments	(8,000)	(33,000)	(20,000)	(218,000)
Transfers to ORE	0	0	0	(291,000)
Net Additions/Deletions	0	62,000	0	724,000
Ending Balance	217,000	943,000	217,000	943,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Beginning Balance	32,000	63,000	41,000	60,000
Charge-Offs	0	0	0	0
Payments	(3,000)	(19,000)	(12,000)	(16,000)
Transfers to ORE	0	0	0	0
Net Additions/Deletions	0	1,064,000	0	1,064,000
Ending Balance	29,000	1,108,000	29,000	1,108,000
Retail Portfolio Segment [Member] | Originated Loan [Member] | Home Equity and Other [Member]
Beginning Balance	1,019,000	1,050,000	1,127,000	385,000
Charge-Offs	0	0	0	0
Payments	(81,000)	(17,000)	(238,000)	(69,000)
Transfers to ORE	0	0	0	0
Net Additions/Deletions	0	69,000	49,000	786,000
Ending Balance	938,000	1,102,000	938,000	1,102,000
Retail Portfolio Segment [Member] | Originated Loan [Member] | One to Four Family Mortgages [Member]
Beginning Balance	143,000	151,000	146,000	157,000
Charge-Offs	0	0	0	0
Payments	(1,000)	(3,000)	(4,000)	(9,000)
Transfers to ORE	0	0	0	0
Net Additions/Deletions	0	0	0	0
Ending Balance	142,000	148,000	142,000	148,000
Retail Portfolio Segment [Member] | Acquired Loan [Member] | Home Equity and Other [Member]
Beginning Balance	302,000	202,000	219,000	208,000
Charge-Offs	0	0	(30,000)	(25,000)
Payments	(2,000)	(8,000)	(40,000)	(49,000)
Transfers to ORE	0	0	(82,000)	0
Net Additions/Deletions	0	92,000	233,000	152,000
Ending Balance	300,000	286,000	300,000	286,000
Retail Portfolio Segment [Member] | Acquired Loan [Member] | One to Four Family Mortgages [Member]
Beginning Balance	400,000	510,000	393,000	326,000
Charge-Offs	0	0	0	0
Payments	(9,000)	(6,000)	(26,000)	(12,000)
Transfers to ORE	0	0	0	0
Net Additions/Deletions	13,000	50,000	37,000	240,000
Ending Balance	$ 404,000	$ 554,000	$ 404,000	$ 554,000