Note 4 - Loans and Allowance for Loan Losses - Activity for Troubled Debt Restructurings (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Commercial and Industrial [Member]
Beginning Balance	$ 1,503,000	$ 2,028,000	$ 7,026,000
Charge-Offs	0	0	0
Payments	(2,021,000)	(555,000)	(6,648,000)
Transfers to ORE	0	0	0
Net Additions/Deletions	3,507,000	30,000	1,650,000
Ending Balance	2,989,000	1,503,000	2,028,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Beginning Balance	1,488,000	2,086,000	2,680,000
Charge-Offs	0	0	0
Payments	(1,105,000)	(598,000)	(594,000)
Transfers to ORE	0	0	0
Net Additions/Deletions	0	0	0
Ending Balance	383,000	1,488,000	2,086,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Owner Occupied Loan [Member]
Beginning Balance	906,000	1,400,000	17,160,000
Charge-Offs	0	0	(4,198,000)
Payments	(242,000)	(591,000)	(11,562,000)
Transfers to ORE	0	0	0
Net Additions/Deletions	935,000	97,000	0
Ending Balance	1,599,000	906,000	1,400,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Non Owner Occupied Loan [Member]
Beginning Balance	5,110,000	10,657,000	17,439,000
Charge-Offs	0	0	0
Payments	(232,000)	(6,004,000)	(6,782,000)
Transfers to ORE	0	0	0
Net Additions/Deletions	(4,878,000)	457,000	0
Ending Balance	0	5,110,000	10,657,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Beginning Balance	716,000	476,000	505,000
Charge-Offs	0	0	0
Payments	(405,000)	(30,000)	(29,000)
Transfers to ORE	0	0	0
Net Additions/Deletions	(311,000)	270,000	0
Ending Balance	0	716,000	476,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Commercial and Industrial [Member]
Beginning Balance	1,125,000	1,686,000	1,439,000
Charge-Offs	0	(48,000)	0
Payments	(550,000)	(513,000)	(444,000)
Transfers to ORE	0	0	0
Net Additions/Deletions	426,000	0	691,000
Ending Balance	1,001,000	1,125,000	1,686,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Beginning Balance	0	0	0
Charge-Offs	0	0	0
Payments	(33,000)	0	0
Transfers to ORE	0	0	0
Net Additions/Deletions	33,000	0	0
Ending Balance	0	0	0
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Owner Occupied Loan [Member]
Beginning Balance	900,000	1,652,000	1,569,000
Charge-Offs	(249,000)	0	(31,000)
Payments	(257,000)	(1,514,000)	(590,000)
Transfers to ORE	0	0	0
Net Additions/Deletions	33,000	762,000	704,000
Ending Balance	427,000	900,000	1,652,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Non Owner Occupied Loan [Member]
Beginning Balance	728,000	647,000	64,000
Charge-Offs	0	0	0
Payments	(922,000)	(110,000)	(9,000)
Transfers to ORE	(291,000)	0	0
Net Additions/Deletions	722,000	191,000	592,000
Ending Balance	237,000	728,000	647,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Beginning Balance	60,000	331,000	381,000
Charge-Offs	0	0	(42,000)
Payments	(1,084,000)	(278,000)	(342,000)
Transfers to ORE	0	0	0
Net Additions/Deletions	1,065,000	7,000	334,000
Ending Balance	41,000	60,000	331,000
Retail Portfolio Segment [Member] | Originated Loan [Member] | Home Equity and Other [Member]
Beginning Balance	385,000	146,000	0
Charge-Offs	0	0	0
Payments	(57,000)	(1,000)	0
Transfers to ORE	0	0	0
Net Additions/Deletions	799,000	240,000	146,000
Ending Balance	1,127,000	385,000	146,000
Retail Portfolio Segment [Member] | Originated Loan [Member] | One to Four Family Mortgages [Member]
Beginning Balance	157,000	128,000	1,967,000
Charge-Offs	0	0	(148,000)
Payments	(11,000)	(11,000)	(1,691,000)
Transfers to ORE	0	0	0
Net Additions/Deletions	0	40,000	0
Ending Balance	146,000	157,000	128,000
Retail Portfolio Segment [Member] | Acquired Loan [Member] | Home Equity and Other [Member]
Beginning Balance	208,000	141,000	26,000
Charge-Offs	(25,000)	0	0
Payments	(121,000)	(30,000)	(39,000)
Transfers to ORE	0	0	0
Net Additions/Deletions	157,000	97,000	154,000
Ending Balance	219,000	208,000	141,000
Retail Portfolio Segment [Member] | Acquired Loan [Member] | One to Four Family Mortgages [Member]
Beginning Balance	326,000	316,000	178,000
Charge-Offs	0	0	0
Payments	(188,000)	(9,000)	(3,000)
Transfers to ORE	0	0	0
Net Additions/Deletions	255,000	19,000	141,000
Ending Balance	$ 393,000	$ 326,000	$ 316,000