Note 3 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans - Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Balance			$ 8,300	$ 8,297	$ 8,297
Charge-offs			(689)	(1,267)	(1,806)
Recoveries			138	123	159
Provision for loan losses	$ 201	$ 291	724	1,148	1,650
Balance	8,473	8,301	8,473	8,301	8,300
Real Estate Construction Portfolio Segment[Member]
Balance			438	576	576
Charge-offs			0	(29)	(29)
Recoveries			0	0	0
Provision for loan losses			(140)	(43)	(109)
Balance	298	504	298	504	438
Consumer Real Estate Portfolio Segment [Member]
Balance			1,830	1,866	1,866
Charge-offs			(146)	(131)	(133)
Recoveries			1	2	2
Provision for loan losses			337	111	95
Balance	2,022	1,848	2,022	1,848	1,830
Commercial Real Estate Portfolio Segment [Member]
Balance			3,738	4,109	4,109
Charge-offs			(122)	(149)	(488)
Recoveries			44	71	83
Provision for loan losses			33	(525)	34
Balance	3,693	3,506	3,693	3,506	3,738
Commercial Non Real Estate Segment [Member]
Balance			1,063	655	655
Charge-offs			(73)	(767)	(883)
Recoveries			14	6	10
Provision for loan losses			111	1,493	1,281
Balance	1,115	1,387	1,115	1,387	1,063
Public Sector and IDA Portfolio Segment[Member]
Balance			330	436	436
Charge-offs			0	0	0
Recoveries			0	0	0
Provision for loan losses			55	(66)	(106)
Balance	385	370	385	370	330
Consumer Non Real Estate Portfolio Segment [Member]
Balance			644	627	627
Charge-offs			(348)	(191)	(273)
Recoveries			79	44	64
Provision for loan losses			357	152	226
Balance	732	632	732	632	644
Unallocated Financing Receivables [Member]
Balance			257	28	28
Charge-offs			0	0	0
Recoveries			0	0	0
Provision for loan losses			(29)	26	229
Balance	$ 228	$ 54	$ 228	$ 54	$ 257