Note 3 - Loans - Aging of the Recorded Investment in Loans (Details) - USD ($)	Sep. 30, 2016	Dec. 31, 2015
Commercial and Industrial Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past due	$ 40,000	$ 238,000
Commercial and Industrial Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past due	140,000	327,000
Commercial and Industrial Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due	2,177,000	3,643,000
Commercial and Industrial Portfolio Segment [Member]
Past due	2,357,000	4,208,000
Current	706,151,000	640,190,000
Loans	708,508,000	644,398,000
Recorded investment greater than 90 days and accruing
Construction and Development Excluding Undeveloped Land Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past due	235,000
Construction and Development Excluding Undeveloped Land Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past due	214,000
Construction and Development Excluding Undeveloped Land Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due	910,000
Construction and Development Excluding Undeveloped Land Portfolio Segment [Member]
Past due	1,359,000
Current	170,635,000	134,482,000
Loans	171,994,000	134,482,000
Recorded investment greater than 90 days and accruing
Undevelopment Land Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past due
Undevelopment Land Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past due
Undevelopment Land Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due	654,000
Undevelopment Land Portfolio Segment [Member]
Past due	654,000
Current	19,339,000	21,185,000
Loans	19,993,000	21,185,000
Recorded investment greater than 90 days and accruing
Real Estate Mortgage Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Investment [Member]
Past due	380,000	290,000
Real Estate Mortgage Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member] | Owner Occupied Commercial [Member]
Past due	1,220,000
Real Estate Mortgage Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member] | One to Four Family Residential [Member]
Past due	1,292,000	1,147,000
Real Estate Mortgage Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member] | Home Equity First Lien [Member]
Past due		35,000
Real Estate Mortgage Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member] | Home Equity Junior Lien [Member]
Past due	641,000	285,000
Real Estate Mortgage Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past due	3,533,000	1,757,000
Real Estate Mortgage Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Investment [Member]
Past due	171,000	140,000
Real Estate Mortgage Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member] | Owner Occupied Commercial [Member]
Past due	331,000
Real Estate Mortgage Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member] | One to Four Family Residential [Member]
Past due	966,000	94,000
Real Estate Mortgage Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member] | Home Equity First Lien [Member]
Past due		51,000
Real Estate Mortgage Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member] | Home Equity Junior Lien [Member]
Past due	31,000	173,000
Real Estate Mortgage Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past due	1,499,000	458,000
Real Estate Mortgage Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Investment [Member]
Past due	94,000	278,000
Real Estate Mortgage Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Owner Occupied Commercial [Member]
Past due	1,548,000	2,761,000
Real Estate Mortgage Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | One to Four Family Residential [Member]
Past due	954,000	1,082,000
Real Estate Mortgage Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Home Equity First Lien [Member]
Past due	46,000	13,000
Real Estate Mortgage Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Home Equity Junior Lien [Member]
Past due	560,000	92,000
Real Estate Mortgage Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due	3,202,000	4,226,000
Real Estate Mortgage Portfolio Segment [Member] | Commercial Investment [Member]
Past due	645,000	708,000
Current	509,483,000	436,281,000
Loans	510,128,000	436,989,000
Recorded investment greater than 90 days and accruing
Real Estate Mortgage Portfolio Segment [Member] | Owner Occupied Commercial [Member]
Past due	3,099,000	2,761,000
Current	409,634,000	417,905,000
Loans	412,733,000	420,666,000
Recorded investment greater than 90 days and accruing
Real Estate Mortgage Portfolio Segment [Member] | One to Four Family Residential [Member]
Past due	3,212,000	2,323,000
Current	242,017,000	224,252,000
Loans	245,229,000	226,575,000
Recorded investment greater than 90 days and accruing	34,000	176,000
Real Estate Mortgage Portfolio Segment [Member] | Home Equity First Lien [Member]
Past due	46,000	99,000
Current	54,791,000	50,016,000
Loans	54,837,000	50,115,000
Recorded investment greater than 90 days and accruing	46,000
Real Estate Mortgage Portfolio Segment [Member] | Home Equity Junior Lien [Member]
Past due	1,232,000	550,000
Current	64,373,000	62,516,000
Loans	65,605,000	63,066,000
Recorded investment greater than 90 days and accruing
Real Estate Mortgage Portfolio Segment [Member]
Past due	8,234,000	6,441,000
Current	1,280,298,000	1,190,970,000
Loans	1,288,532,000	1,197,411,000
Recorded investment greater than 90 days and accruing	80,000	176,000
Consumer Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Past due	16,000	343,000
Consumer Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Past due	1,000	8,000
Consumer Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due	26,000
Consumer Portfolio Segment [Member]
Past due	43,000	351,000
Current	33,636,000	35,180,000
Loans	33,679,000	35,531,000
Recorded investment greater than 90 days and accruing
Financing Receivables, 30 to 59 Days Past Due [Member]
Past due	3,824,000	2,338,000
Financing Receivables, 60 to 89 Days Past Due [Member]
Past due	1,854,000	793,000
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Past due	6,969,000	7,869,000
Past due	12,647,000	11,000,000
Current	2,210,059,000	2,022,007,000
Loans	2,222,706,000	2,033,007,000
Recorded investment greater than 90 days and accruing	$ 80,000	$ 176,000