Note 4 - Loans Held for Investment - Risk Ratings (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Credit exposure by assigned risk grade	$ 701,443,000	$ 607,865,000
Consumer Portfolio Segment [Member]
Credit exposure by assigned risk grade	69,209,000	62,857,000
Consumer Portfolio Segment [Member] | Real Estate Loan [Member]
Credit exposure by assigned risk grade	16,967,000	17,239,000
Consumer Portfolio Segment [Member] | Construction Loans [Member]
Credit exposure by assigned risk grade	105,000	196,000
Consumer Portfolio Segment [Member] | Lots and Raw Land [Member]
Credit exposure by assigned risk grade	8,975,000	9,643,000
Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Credit exposure by assigned risk grade	36,815,000	29,709,000
Consumer Portfolio Segment [Member] | Other Loans [Member]
Credit exposure by assigned risk grade	6,347,000	6,070,000
Consumer Portfolio Segment [Member] | Lease Receivables [Member]
Credit exposure by assigned risk grade	8,975,000	9,643,000
Commercial Portfolio Segment [Member]
Credit exposure by assigned risk grade	556,941,000	472,688,000
Commercial Portfolio Segment [Member] | Real Estate Loan [Member]
Credit exposure by assigned risk grade	378,173,000	338,714,000
Commercial Portfolio Segment [Member] | Construction Loans [Member]
Credit exposure by assigned risk grade	56,118,000	42,987,000
Commercial Portfolio Segment [Member] | Lots and Raw Land [Member]
Credit exposure by assigned risk grade	33,434,000	28,271,000
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Credit exposure by assigned risk grade	67,980,000	45,481,000
Commercial Portfolio Segment [Member] | Lease Receivables [Member]
Credit exposure by assigned risk grade	21,236,000	17,235,000
Residential Portfolio Segment [Member]
Credit exposure by assigned risk grade	75,293,000	72,320,000
Residential Portfolio Segment [Member] | Real Estate Loan [Member]
Credit exposure by assigned risk grade	67,264,000	68,229,000
Residential Portfolio Segment [Member] | Construction Loans [Member]
Credit exposure by assigned risk grade	7,875,000	3,934,000
Residential Portfolio Segment [Member] | Lots and Raw Land [Member]
Credit exposure by assigned risk grade	154,000	157,000
Residential Portfolio Segment [Member] | Lease Receivables [Member]
Credit exposure by assigned risk grade	21,236,000	17,235,000
Pass [Member] | Consumer Portfolio Segment [Member] | Real Estate Loan [Member]
Credit exposure by assigned risk grade	16,472,000	16,253,000
Pass [Member] | Consumer Portfolio Segment [Member] | Construction Loans [Member]
Credit exposure by assigned risk grade	105,000	196,000
Pass [Member] | Consumer Portfolio Segment [Member] | Lots and Raw Land [Member]
Credit exposure by assigned risk grade	8,595,000	7,906,000
Pass [Member] | Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Credit exposure by assigned risk grade	36,474,000	29,523,000
Pass [Member] | Consumer Portfolio Segment [Member] | Other Loans [Member]
Credit exposure by assigned risk grade	6,345,000	6,000,000
Pass [Member] | Residential Portfolio Segment [Member] | Real Estate Loan [Member]
Credit exposure by assigned risk grade	65,406,000	65,977,000
Pass [Member] | Residential Portfolio Segment [Member] | Construction Loans [Member]
Credit exposure by assigned risk grade	7,875,000	3,934,000
Pass [Member] | Residential Portfolio Segment [Member] | Lots and Raw Land [Member]
Credit exposure by assigned risk grade	154,000	157,000
Pass [Member] | Residential Portfolio Segment [Member] | Lease Receivables [Member]
Credit exposure by assigned risk grade	21,236,000	17,140,000
Excellent [Member] | Commercial Portfolio Segment [Member] | Real Estate Loan [Member]
Credit exposure by assigned risk grade
Excellent [Member] | Commercial Portfolio Segment [Member] | Construction Loans [Member]
Credit exposure by assigned risk grade
Excellent [Member] | Commercial Portfolio Segment [Member] | Lots and Raw Land [Member]
Credit exposure by assigned risk grade
Excellent [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Credit exposure by assigned risk grade	72,000
Special Mention [Member] | Consumer Portfolio Segment [Member] | Real Estate Loan [Member]
Credit exposure by assigned risk grade	252,000	679,000
Special Mention [Member] | Consumer Portfolio Segment [Member] | Construction Loans [Member]
Credit exposure by assigned risk grade
Special Mention [Member] | Consumer Portfolio Segment [Member] | Lots and Raw Land [Member]
Credit exposure by assigned risk grade	211,000	1,270,000
Special Mention [Member] | Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Credit exposure by assigned risk grade	84,000	61,000
Special Mention [Member] | Consumer Portfolio Segment [Member] | Other Loans [Member]
Credit exposure by assigned risk grade	2,000	26,000
Special Mention [Member] | Commercial Portfolio Segment [Member] | Real Estate Loan [Member]
Credit exposure by assigned risk grade	3,424,000	7,872,000
Special Mention [Member] | Commercial Portfolio Segment [Member] | Construction Loans [Member]
Credit exposure by assigned risk grade	129,000	860,000
Special Mention [Member] | Commercial Portfolio Segment [Member] | Lots and Raw Land [Member]
Credit exposure by assigned risk grade	1,384,000	2,715,000
Special Mention [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Credit exposure by assigned risk grade	672,000	41,000
Special Mention [Member] | Residential Portfolio Segment [Member] | Real Estate Loan [Member]
Credit exposure by assigned risk grade	761,000	791,000
Special Mention [Member] | Residential Portfolio Segment [Member] | Construction Loans [Member]
Credit exposure by assigned risk grade
Special Mention [Member] | Residential Portfolio Segment [Member] | Lots and Raw Land [Member]
Credit exposure by assigned risk grade
Special Mention [Member] | Residential Portfolio Segment [Member] | Lease Receivables [Member]
Credit exposure by assigned risk grade
Above Average [Member] | Commercial Portfolio Segment [Member] | Real Estate Loan [Member]
Credit exposure by assigned risk grade	2,567,000	2,788,000
Above Average [Member] | Commercial Portfolio Segment [Member] | Construction Loans [Member]
Credit exposure by assigned risk grade
Above Average [Member] | Commercial Portfolio Segment [Member] | Lots and Raw Land [Member]
Credit exposure by assigned risk grade	203,000	160,000
Above Average [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Credit exposure by assigned risk grade	520,000	3,757,000
Substandard [Member] | Consumer Portfolio Segment [Member] | Real Estate Loan [Member]
Credit exposure by assigned risk grade	243,000	307,000
Substandard [Member] | Consumer Portfolio Segment [Member] | Construction Loans [Member]
Credit exposure by assigned risk grade
Substandard [Member] | Consumer Portfolio Segment [Member] | Lots and Raw Land [Member]
Credit exposure by assigned risk grade	169,000	277,000
Substandard [Member] | Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Credit exposure by assigned risk grade	257,000	125,000
Substandard [Member] | Consumer Portfolio Segment [Member] | Other Loans [Member]
Credit exposure by assigned risk grade		44,000
Substandard [Member] | Commercial Portfolio Segment [Member] | Real Estate Loan [Member]
Credit exposure by assigned risk grade	4,351,000	8,093,000
Substandard [Member] | Commercial Portfolio Segment [Member] | Construction Loans [Member]
Credit exposure by assigned risk grade		574,000
Substandard [Member] | Commercial Portfolio Segment [Member] | Lots and Raw Land [Member]
Credit exposure by assigned risk grade	541,000	1,242,000
Substandard [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Credit exposure by assigned risk grade	2,190,000	2,020,000
Substandard [Member] | Residential Portfolio Segment [Member] | Real Estate Loan [Member]
Credit exposure by assigned risk grade	1,097,000	1,461,000
Substandard [Member] | Residential Portfolio Segment [Member] | Construction Loans [Member]
Credit exposure by assigned risk grade
Substandard [Member] | Residential Portfolio Segment [Member] | Lots and Raw Land [Member]
Credit exposure by assigned risk grade
Substandard [Member] | Residential Portfolio Segment [Member] | Lease Receivables [Member]
Credit exposure by assigned risk grade		95,000
Average [Member] | Commercial Portfolio Segment [Member] | Real Estate Loan [Member]
Credit exposure by assigned risk grade	112,489,000	98,148,000
Average [Member] | Commercial Portfolio Segment [Member] | Construction Loans [Member]
Credit exposure by assigned risk grade	13,986,000	10,023,000
Average [Member] | Commercial Portfolio Segment [Member] | Lots and Raw Land [Member]
Credit exposure by assigned risk grade	2,237,000	2,247,000
Average [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Credit exposure by assigned risk grade	14,331,000	8,095,000
Doubtful [Member] | Consumer Portfolio Segment [Member] | Real Estate Loan [Member]
Credit exposure by assigned risk grade
Doubtful [Member] | Consumer Portfolio Segment [Member] | Construction Loans [Member]
Credit exposure by assigned risk grade
Doubtful [Member] | Consumer Portfolio Segment [Member] | Lots and Raw Land [Member]
Credit exposure by assigned risk grade		190,000
Doubtful [Member] | Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Credit exposure by assigned risk grade
Doubtful [Member] | Consumer Portfolio Segment [Member] | Other Loans [Member]
Credit exposure by assigned risk grade
Doubtful [Member] | Commercial Portfolio Segment [Member] | Real Estate Loan [Member]
Credit exposure by assigned risk grade
Doubtful [Member] | Commercial Portfolio Segment [Member] | Construction Loans [Member]
Credit exposure by assigned risk grade
Doubtful [Member] | Commercial Portfolio Segment [Member] | Lots and Raw Land [Member]
Credit exposure by assigned risk grade
Doubtful [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Credit exposure by assigned risk grade
Doubtful [Member] | Residential Portfolio Segment [Member] | Real Estate Loan [Member]
Credit exposure by assigned risk grade
Doubtful [Member] | Residential Portfolio Segment [Member] | Construction Loans [Member]
Credit exposure by assigned risk grade
Doubtful [Member] | Residential Portfolio Segment [Member] | Lots and Raw Land [Member]
Credit exposure by assigned risk grade
Doubtful [Member] | Residential Portfolio Segment [Member] | Lease Receivables [Member]
Credit exposure by assigned risk grade
Acceptable [Member] | Commercial Portfolio Segment [Member] | Real Estate Loan [Member]
Credit exposure by assigned risk grade	237,473,000	209,936,000
Acceptable [Member] | Commercial Portfolio Segment [Member] | Construction Loans [Member]
Credit exposure by assigned risk grade	40,819,000	31,139,000
Acceptable [Member] | Commercial Portfolio Segment [Member] | Lots and Raw Land [Member]
Credit exposure by assigned risk grade	22,042,000	18,086,000
Acceptable [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Credit exposure by assigned risk grade	48,305,000	30,218,000
Unlikely to be Collected Financing Receivable [Member] | Consumer Portfolio Segment [Member] | Real Estate Loan [Member]
Credit exposure by assigned risk grade
Unlikely to be Collected Financing Receivable [Member] | Consumer Portfolio Segment [Member] | Construction Loans [Member]
Credit exposure by assigned risk grade
Unlikely to be Collected Financing Receivable [Member] | Consumer Portfolio Segment [Member] | Lots and Raw Land [Member]
Credit exposure by assigned risk grade
Unlikely to be Collected Financing Receivable [Member] | Consumer Portfolio Segment [Member] | Home Equity Loan [Member]
Credit exposure by assigned risk grade
Unlikely to be Collected Financing Receivable [Member] | Consumer Portfolio Segment [Member] | Other Loans [Member]
Credit exposure by assigned risk grade
Unlikely to be Collected Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Real Estate Loan [Member]
Credit exposure by assigned risk grade
Unlikely to be Collected Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Construction Loans [Member]
Credit exposure by assigned risk grade
Unlikely to be Collected Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Lots and Raw Land [Member]
Credit exposure by assigned risk grade
Unlikely to be Collected Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Credit exposure by assigned risk grade
Unlikely to be Collected Financing Receivable [Member] | Residential Portfolio Segment [Member] | Real Estate Loan [Member]
Credit exposure by assigned risk grade
Unlikely to be Collected Financing Receivable [Member] | Residential Portfolio Segment [Member] | Construction Loans [Member]
Credit exposure by assigned risk grade
Unlikely to be Collected Financing Receivable [Member] | Residential Portfolio Segment [Member] | Lots and Raw Land [Member]
Credit exposure by assigned risk grade
Unlikely to be Collected Financing Receivable [Member] | Residential Portfolio Segment [Member] | Lease Receivables [Member]
Credit exposure by assigned risk grade
Watch [Member] | Commercial Portfolio Segment [Member] | Real Estate Loan [Member]
Credit exposure by assigned risk grade	17,869,000	11,877,000
Watch [Member] | Commercial Portfolio Segment [Member] | Construction Loans [Member]
Credit exposure by assigned risk grade	1,184,000	391,000
Watch [Member] | Commercial Portfolio Segment [Member] | Lots and Raw Land [Member]
Credit exposure by assigned risk grade	7,027,000	3,821,000
Watch [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Credit exposure by assigned risk grade	$ 1,890,000	$ 1,350,000