Note 4 - Allowance for Loan Losses, Nonperforming Assets and Impaired Loans - Loans and Allowance for Loan Losses by Evaluation Method (Details) - USD ($)	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2014
Real Estate Construction Portfolio Segment[Member]
Individually evaluated for impairment	$ 0	$ 0
Collectively evaluated for impairment	504,000	576,000
Total	504,000	576,000	$ 535,000	$ 612,000
Individually evaluated for impairment	273,000	718,000
Collectively evaluated for impairment	39,917,000	47,533,000
Total	40,190,000	48,251,000
Consumer Real Estate Portfolio Segment [Member]
Individually evaluated for impairment	27,000	22,000
Collectively evaluated for impairment	1,821,000	1,844,000
Total	1,848,000	1,866,000	1,794,000	1,662,000
Individually evaluated for impairment	889,000	962,000
Collectively evaluated for impairment	150,263,000	142,542,000
Total	151,152,000	143,504,000
Commercial Real Estate Portfolio Segment [Member]
Individually evaluated for impairment	0	23,000
Collectively evaluated for impairment	3,506,000	4,086,000
Total	3,506,000	4,109,000	3,838,000	3,537,000
Individually evaluated for impairment	8,448,000	12,575,000
Collectively evaluated for impairment	316,641,000	296,803,000
Total	325,089,000	309,378,000
Commercial Non Real Estate Segment [Member]
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	1,387,000	655,000
Total	1,387,000	655,000	870,000	1,475,000
Individually evaluated for impairment	297,000	1,091,000
Collectively evaluated for impairment	41,273,000	36,480,000
Total	41,570,000	37,571,000
Public Sector and IDA Portfolio Segment[Member]
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	370,000	436,000
Total	370,000	436,000	497,000	327,000
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	45,957,000	51,335,000
Total	45,957,000	51,335,000
Consumer Non Real Estate Portfolio Segment [Member]
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	632,000	627,000
Total	632,000	627,000	514,000	602,000
Individually evaluated for impairment	3,000	0
Collectively evaluated for impairment	33,076,000	29,845,000
Total	33,079,000	29,845,000
Unallocated Financing Receivables [Member]
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	54,000	28,000
Total	54,000	28,000	69,000	48,000
Individually evaluated for impairment	0	0
Collectively evaluated for impairment	0	0
Total	0	0
Individually evaluated for impairment	27,000	45,000
Collectively evaluated for impairment	8,274,000	8,252,000
Total	8,301,000	8,297,000	$ 8,117,000	$ 8,263,000
Individually evaluated for impairment	9,910,000	15,346,000
Collectively evaluated for impairment	627,127,000	604,538,000
Total	$ 637,037,000	$ 619,884,000