Note 3 - Loans and Allowance for Loan Losses - Activity for Troubled Debt Restructurings (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Commercial and Industrial [Member]
Beginning Balance	$ 2,775,000	$ 2,103,000	$ 1,503,000	$ 2,028,000
Charge-Offs	0	0	0	0
Payments	(572,000)	(230,000)	(1,950,000)	(175,000)
Transfers to ORE	0	0	0	0
Net Additions/Deletions	858,000	0	3,508,000	20,000
Ending Balance	3,061,000	1,873,000	3,061,000	1,873,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Beginning Balance	934,000	2,036,000	1,488,000	2,086,000
Charge-Offs	0	0	0	0
Payments	(276,000)	(526,000)	(830,000)	(576,000)
Transfers to ORE	0	0	0	0
Net Additions/Deletions	0	0	0	0
Ending Balance	658,000	1,510,000	658,000	1,510,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Owner Occupied Loan [Member]
Beginning Balance	1,658,000	1,431,000	906,000	1,400,000
Charge-Offs	0	0	0	0
Payments	(144,000)	(37,000)	(196,000)	(103,000)
Transfers to ORE	0	0	0	0
Net Additions/Deletions	477,000	0	1,281,000	97,000
Ending Balance	1,991,000	1,394,000	1,991,000	1,394,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Non Owner Occupied Loan [Member]
Beginning Balance	564,000	10,435,000	5,110,000	10,657,000
Charge-Offs	0	0	0	0
Payments	(24,000)	(91,000)	(167,000)	(313,000)
Transfers to ORE	0	0	0	0
Net Additions/Deletions	0	0	(4,403,000)	0
Ending Balance	540,000	10,344,000	540,000	10,344,000
Commercial Portfolio Segment [Member] | Originated Loan [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Beginning Balance	131,000	461,000	716,000	476,000
Charge-Offs	0	0	0	0
Payments	(131,000)	(7,000)	(404,000)	(22,000)
Transfers to ORE	0	0	0	0
Net Additions/Deletions	0	0	(312,000)	0
Ending Balance	0	454,000	0	454,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Commercial and Industrial [Member]
Beginning Balance	992,000	1,644,000	1,125,000	1,686,000
Charge-Offs	0	0	0	(48,000)
Payments	(239,000)	(397,000)	(518,000)	(391,000)
Transfers to ORE	0	0	0	0
Net Additions/Deletions	280,000	0	426,000	0
Ending Balance	1,033,000	1,247,000	1,033,000	1,247,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
Beginning Balance	33,000	0	0	0
Charge-Offs	0	0	0	0
Payments	(4,000)	0	(4,000)	0
Transfers to ORE	0	0	0	0
Net Additions/Deletions	0	0	33,000	0
Ending Balance	29,000	0	29,000	0
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Owner Occupied Loan [Member]
Beginning Balance	980,000	1,283,000	900,000	1,652,000
Charge-Offs	(227,000)	0	(239,000)	0
Payments	(253,000)	(747,000)	(161,000)	(1,116,000)
Transfers to ORE	0	0	0	0
Net Additions/Deletions	0	41,000	0	41,000
Ending Balance	500,000	577,000	500,000	577,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Non Owner Occupied Loan [Member]
Beginning Balance	914,000	681,000	728,000	647,000
Charge-Offs	0	0	0	0
Payments	(33,000)	(24,000)	(218,000)	(46,000)
Transfers to ORE	0	0	(291,000)	0
Net Additions/Deletions	62,000	0	724,000	56,000
Ending Balance	943,000	657,000	943,000	657,000
Commercial Portfolio Segment [Member] | Acquired Loan [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
Beginning Balance	63,000	274,000	60,000	331,000
Charge-Offs	0	0	0	0
Payments	(19,000)	(35,000)	(16,000)	(99,000)
Transfers to ORE	0	0	0	0
Net Additions/Deletions	1,064,000	0	1,064,000	7,000
Ending Balance	1,108,000	239,000	1,108,000	239,000
Retail Portfolio Segment [Member] | Originated Loan [Member] | Home Equity and Other [Member]
Beginning Balance	1,050,000	329,000	385,000	146,000
Charge-Offs	0	0	0	0
Payments	(17,000)	(1,000)	(69,000)	(1,000)
Transfers to ORE	0	0	0	0
Net Additions/Deletions	69,000	59,000	786,000	242,000
Ending Balance	1,102,000	387,000	1,102,000	387,000
Retail Portfolio Segment [Member] | Originated Loan [Member] | One to Four Family Mortgages [Member]
Beginning Balance	151,000	163,000	157,000	128,000
Charge-Offs	0	0	0	0
Payments	(3,000)	(3,000)	(9,000)	(8,000)
Transfers to ORE	0	0	0	0
Net Additions/Deletions	0	0	0	40,000
Ending Balance	148,000	160,000	148,000	160,000
Retail Portfolio Segment [Member] | Acquired Loan [Member] | Home Equity and Other [Member]
Beginning Balance	202,000	180,000	208,000	141,000
Charge-Offs	0	0	(25,000)	0
Payments	(8,000)	(7,000)	(49,000)	(20,000)
Transfers to ORE	0	0	0	0
Net Additions/Deletions	92,000	3,000	152,000	55,000
Ending Balance	286,000	176,000	286,000	176,000
Retail Portfolio Segment [Member] | Acquired Loan [Member] | One to Four Family Mortgages [Member]
Beginning Balance	510,000	333,000	326,000	316,000
Charge-Offs	0	0	0	0
Payments	(6,000)	(4,000)	(12,000)	(6,000)
Transfers to ORE	0	0	0	0
Net Additions/Deletions	50,000	0	240,000	19,000
Ending Balance	$ 554,000	$ 329,000	$ 554,000	$ 329,000