Note 3 - Loans and Allowance for Loan Losses - Impaired Loans (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Originated Loan [Member]
With no related allowance recorded, unpaid principal balance	$ 2,592,000		$ 2,592,000		$ 4,915,000
With no related allowance recorded, principal balance	1,880,000		1,880,000		3,150,000
With no related allowance recorded, average recorded principal balance	3,248,000	$ 2,516,000	3,216,000	$ 2,498,000
With related allowance recorded, unpaid principal balance	5,326,000		5,326,000		5,837,000
With related allowance recorded, principal balance	4,778,000		4,778,000		5,637,000
Related allowance	674,000		674,000		1,867,000
With related allowance recorded, average recorded principal balance	4,790,000	9,795,000	5,073,000	10,168,000
Total unpaid principal balance	7,918,000		7,918,000		10,752,000
Total principal balance	6,658,000		6,658,000		8,787,000
Total average recorded principal balance	8,038,000	12,311,000	8,289,000	12,666,000
Originated Loan [Member] | Commercial Portfolio Segment [Member]
With no related allowance recorded, unpaid principal balance	872,000		872,000		3,096,000
With no related allowance recorded, principal balance	872,000		872,000		2,014,000
With no related allowance recorded, average recorded principal balance	2,159,000	1,338,000	2,111,000	1,465,000
With related allowance recorded, unpaid principal balance	4,416,000		4,416,000		4,447,000
With related allowance recorded, principal balance	3,940,000		3,940,000		4,380,000
Related allowance	391,000		391,000		1,202,000
With related allowance recorded, average recorded principal balance	3,945,000	8,687,000	4,091,000	9,240,000
Total unpaid principal balance	5,288,000		5,288,000		7,543,000
Total principal balance	4,812,000		4,812,000		6,394,000
Total average recorded principal balance	6,104,000	10,025,000	6,202,000	10,705,000
Originated Loan [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
With no related allowance recorded, unpaid principal balance	513,000		513,000		765,000
With no related allowance recorded, principal balance	513,000		513,000		178,000
With no related allowance recorded, average recorded principal balance	373,000	861,000	308,000	1,073,000
With related allowance recorded, unpaid principal balance	2,390,000		2,390,000		3,038,000
With related allowance recorded, principal balance	2,045,000		2,045,000		2,989,000
Related allowance	198,000		198,000		963,000
With related allowance recorded, average recorded principal balance	2,089,000	3,584,000	2,389,000	3,183,000
Originated Loan [Member] | Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
With no related allowance recorded, unpaid principal balance	99,000		99,000		454,000
With no related allowance recorded, principal balance	99,000		99,000		35,000
With no related allowance recorded, average recorded principal balance	50,000	73,000	45,000	80,000
With related allowance recorded, unpaid principal balance	0		0		0
With related allowance recorded, principal balance	0		0		0
Related allowance	0		0		0
With related allowance recorded, average recorded principal balance	0	499,000	0	665,000
Originated Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
With no related allowance recorded, unpaid principal balance	31,000		31,000		1,528,000
With no related allowance recorded, principal balance	31,000		31,000		1,452,000
With no related allowance recorded, average recorded principal balance	1,453,000	272,000	1,453,000	181,000
With related allowance recorded, unpaid principal balance	1,882,000		1,882,000		1,409,000
With related allowance recorded, principal balance	1,753,000		1,753,000		1,391,000
Related allowance	168,000		168,000		239,000
With related allowance recorded, average recorded principal balance	1,713,000	1,606,000	1,606,000	1,373,000
Originated Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
With no related allowance recorded, unpaid principal balance	0		0		0
With no related allowance recorded, principal balance	0		0		0
With no related allowance recorded, average recorded principal balance	0	0	0	0
With related allowance recorded, unpaid principal balance	0		0		0
With related allowance recorded, principal balance	0		0		0
Related allowance	0		0		0
With related allowance recorded, average recorded principal balance	0	2,479,000	0	3,326,000
Originated Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
With no related allowance recorded, unpaid principal balance	229,000		229,000		349,000
With no related allowance recorded, principal balance	229,000		229,000		349,000
With no related allowance recorded, average recorded principal balance	283,000	132,000	305,000	131,000
With related allowance recorded, unpaid principal balance	144,000		144,000		0
With related allowance recorded, principal balance	142,000		142,000		0
Related allowance	25,000		25,000		0
With related allowance recorded, average recorded principal balance	143,000	519,000	96,000	693,000
Originated Loan [Member] | Retail Portfolio Segment [Member]
With no related allowance recorded, unpaid principal balance	1,720,000		1,720,000		1,819,000
With no related allowance recorded, principal balance	1,008,000		1,008,000		1,136,000
With no related allowance recorded, average recorded principal balance	1,089,000	1,178,000	1,105,000	1,033,000
With related allowance recorded, unpaid principal balance	910,000		910,000		1,390,000
With related allowance recorded, principal balance	838,000		838,000		1,257,000
Related allowance	283,000		283,000		665,000
With related allowance recorded, average recorded principal balance	845,000	1,108,000	982,000	928,000
Total unpaid principal balance	2,630,000		2,630,000		3,209,000
Total principal balance	1,846,000		1,846,000		2,393,000
Total average recorded principal balance	1,934,000	2,286,000	2,087,000	1,961,000
Originated Loan [Member] | Retail Portfolio Segment [Member] | Home Equity and Other [Member]
With no related allowance recorded, unpaid principal balance	636,000		636,000		693,000
With no related allowance recorded, principal balance	617,000		617,000		680,000
With no related allowance recorded, average recorded principal balance	684,000	531,000	683,000	392,000
With related allowance recorded, unpaid principal balance	500,000		500,000		1,225,000
With related allowance recorded, principal balance	490,000		490,000		1,147,000
Related allowance	232,000		232,000		652,000
With related allowance recorded, average recorded principal balance	494,000	993,000	712,000	799,000
Originated Loan [Member] | Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
With no related allowance recorded, unpaid principal balance	1,084,000		1,084,000		1,126,000
With no related allowance recorded, principal balance	391,000		391,000		456,000
With no related allowance recorded, average recorded principal balance	405,000	647,000	422,000	641,000
With related allowance recorded, unpaid principal balance	410,000		410,000		165,000
With related allowance recorded, principal balance	348,000		348,000		110,000
Related allowance	51,000		51,000		13,000
With related allowance recorded, average recorded principal balance	351,000	115,000	270,000	129,000
Acquired Loan [Member]
With no related allowance recorded, unpaid principal balance	5,366,000		5,366,000		5,938,000
With no related allowance recorded, principal balance	4,376,000		4,376,000		4,795,000
With no related allowance recorded, average recorded principal balance	4,377,000	5,523,000	4,517,000	5,313,000
With related allowance recorded, unpaid principal balance	35,000		35,000		0
With related allowance recorded, principal balance	35,000		35,000		0
Related allowance	35,000		35,000		0
With related allowance recorded, average recorded principal balance	816,000	233,000	545,000	235,000
Total unpaid principal balance	5,401,000		5,401,000		5,938,000
Total principal balance	4,411,000		4,411,000		4,795,000
Total average recorded principal balance	5,193,000	5,756,000	5,062,000	5,548,000
Acquired Loan [Member] | Commercial Portfolio Segment [Member]
With no related allowance recorded, unpaid principal balance	2,035,000		2,035,000		2,541,000
With no related allowance recorded, principal balance	1,612,000		1,612,000		2,135,000
With no related allowance recorded, average recorded principal balance	1,667,000	3,346,000	1,824,000	3,202,000
With related allowance recorded, unpaid principal balance	0		0		0
With related allowance recorded, principal balance	0		0		0
Related allowance	0		0		0
With related allowance recorded, average recorded principal balance	799,000	62,000	533,000	64,000
Total unpaid principal balance	2,035,000		2,035,000		2,541,000
Total principal balance	1,612,000		1,612,000		2,135,000
Total average recorded principal balance	2,466,000	3,408,000	2,357,000	3,266,000
Acquired Loan [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
With no related allowance recorded, unpaid principal balance	717,000		717,000		1,039,000
With no related allowance recorded, principal balance	708,000		708,000		1,021,000
With no related allowance recorded, average recorded principal balance	720,000	1,146,000	821,000	1,040,000
With related allowance recorded, unpaid principal balance	0		0		0
With related allowance recorded, principal balance	0		0		0
Related allowance	0		0		0
With related allowance recorded, average recorded principal balance	0	15,000	0	16,000
Acquired Loan [Member] | Commercial Portfolio Segment [Member] | Vacant Land and Land Development and Residential Construction Loan [Member]
With no related allowance recorded, unpaid principal balance	0		0		0
With no related allowance recorded, principal balance	0		0		0
With no related allowance recorded, average recorded principal balance	0	17,000	0	11,000
With related allowance recorded, unpaid principal balance	0		0		0
With related allowance recorded, principal balance	0		0		0
Related allowance	0		0		0
With related allowance recorded, average recorded principal balance	0	0	0	0
Acquired Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
With no related allowance recorded, unpaid principal balance	1,035,000		1,035,000		1,027,000
With no related allowance recorded, principal balance	639,000		639,000		659,000
With no related allowance recorded, average recorded principal balance	677,000	1,125,000	671,000	1,153,000
With related allowance recorded, unpaid principal balance	0		0		0
With related allowance recorded, principal balance	0		0		0
Related allowance	0		0		0
With related allowance recorded, average recorded principal balance	799,000	47,000	533,000	48,000
Acquired Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
With no related allowance recorded, unpaid principal balance	225,000		225,000		238,000
With no related allowance recorded, principal balance	225,000		225,000		237,000
With no related allowance recorded, average recorded principal balance	228,000	837,000	231,000	821,000
With related allowance recorded, unpaid principal balance	0		0		0
With related allowance recorded, principal balance	0		0		0
Related allowance	0		0		0
With related allowance recorded, average recorded principal balance	0	0	0	0
Acquired Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
With no related allowance recorded, unpaid principal balance	58,000		58,000		237,000
With no related allowance recorded, principal balance	40,000		40,000		218,000
With no related allowance recorded, average recorded principal balance	42,000	221,000	101,000	177,000
With related allowance recorded, unpaid principal balance	0		0		0
With related allowance recorded, principal balance	0		0		0
Related allowance	0		0		0
With related allowance recorded, average recorded principal balance	0	0	0	0
Acquired Loan [Member] | Retail Portfolio Segment [Member]
With no related allowance recorded, unpaid principal balance	3,331,000		3,331,000		3,397,000
With no related allowance recorded, principal balance	2,764,000		2,764,000		2,660,000
With no related allowance recorded, average recorded principal balance	2,710,000	2,177,000	2,693,000	2,111,000
With related allowance recorded, unpaid principal balance	35,000		35,000		0
With related allowance recorded, principal balance	35,000		35,000		0
Related allowance	35,000		35,000		0
With related allowance recorded, average recorded principal balance	17,000	171,000	12,000	171,000
Total unpaid principal balance	3,366,000		3,366,000		3,397,000
Total principal balance	2,799,000		2,799,000		2,660,000
Total average recorded principal balance	2,727,000	2,348,000	2,705,000	2,282,000
Acquired Loan [Member] | Retail Portfolio Segment [Member] | Home Equity and Other [Member]
With no related allowance recorded, unpaid principal balance	818,000		818,000		694,000
With no related allowance recorded, principal balance	771,000		771,000		507,000
With no related allowance recorded, average recorded principal balance	710,000	366,000	642,000	361,000
With related allowance recorded, unpaid principal balance	35,000		35,000		0
With related allowance recorded, principal balance	35,000		35,000		0
Related allowance	35,000		35,000		0
With related allowance recorded, average recorded principal balance	17,000	0	12,000	0
Acquired Loan [Member] | Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
With no related allowance recorded, unpaid principal balance	2,513,000		2,513,000		2,703,000
With no related allowance recorded, principal balance	1,993,000		1,993,000		2,153,000
With no related allowance recorded, average recorded principal balance	2,000,000	1,811,000	2,051,000	1,750,000
With related allowance recorded, unpaid principal balance	0		0		0
With related allowance recorded, principal balance	0		0		0
Related allowance	0		0		$ 0
With related allowance recorded, average recorded principal balance	$ 0	$ 171,000	$ 0	$ 171,000