Note 4 - Loans and Allowance for Loan Losses - Impaired Loans (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Originated Loan [Member]
With no related allowance recorded, unpaid principal balance	$ 10,990,000	$ 4,915,000
With no related allowance recorded, principal balance	10,306,000	3,150,000
With no related allowance recorded, average recorded principal balance	4,598,000	2,580,000
With related allowance recorded, unpaid principal balance	8,660,000	5,837,000
With related allowance recorded, principal balance	8,576,000	5,637,000
Related allowance	689,000	1,867,000
With related allowance recorded, average recorded principal balance	6,538,000	8,954,000
Total unpaid principal balance	19,650,000	10,752,000
Total principal balance	18,882,000	8,787,000
Total average recorded principal balance	11,136,000	11,534,000
Originated Loan [Member] | Commercial Portfolio Segment [Member]
With no related allowance recorded, unpaid principal balance	9,330,000	3,096,000
With no related allowance recorded, principal balance	9,330,000	2,014,000
With no related allowance recorded, average recorded principal balance	3,493,000	1,458,000
With related allowance recorded, unpaid principal balance	7,809,000	4,447,000
With related allowance recorded, principal balance	7,804,000	4,380,000
Related allowance	451,000	1,202,000
With related allowance recorded, average recorded principal balance	5,639,000	7,910,000
Total unpaid principal balance	17,139,000	7,543,000
Total principal balance	17,134,000	6,394,000
Total average recorded principal balance	9,132,000	9,368,000
Originated Loan [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
With no related allowance recorded, unpaid principal balance	8,604,000	765,000
With no related allowance recorded, principal balance	8,604,000	178,000
With no related allowance recorded, average recorded principal balance	2,096,000	694,000
With related allowance recorded, unpaid principal balance	5,011,000	3,038,000
With related allowance recorded, principal balance	5,011,000	2,989,000
Related allowance	83,000	963,000
With related allowance recorded, average recorded principal balance	3,455,000	3,314,000
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	94,000	454,000
With no related allowance recorded, principal balance	94,000	35,000
With no related allowance recorded, average recorded principal balance	65,000	65,000
With related allowance recorded, unpaid principal balance	0	0
With related allowance recorded, principal balance	0	0
Related allowance	0	0
With related allowance recorded, average recorded principal balance	0	449,000
Originated Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
With no related allowance recorded, unpaid principal balance	632,000	1,528,000
With no related allowance recorded, principal balance	632,000	1,452,000
With no related allowance recorded, average recorded principal balance	1,145,000	442,000
With related allowance recorded, unpaid principal balance	2,658,000	1,409,000
With related allowance recorded, principal balance	2,658,000	1,391,000
Related allowance	363,000	239,000
With related allowance recorded, average recorded principal balance	2,072,000	1,663,000
Originated Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
With no related allowance recorded, unpaid principal balance	0	0
With no related allowance recorded, principal balance	0	0
With no related allowance recorded, average recorded principal balance	0	36,000
With related allowance recorded, unpaid principal balance	0	0
With related allowance recorded, principal balance	0	0
Related allowance	0	0
With related allowance recorded, average recorded principal balance	0	2,055,000
Originated Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
With no related allowance recorded, unpaid principal balance	0	349,000
With no related allowance recorded, principal balance	0	349,000
With no related allowance recorded, average recorded principal balance	187,000	221,000
With related allowance recorded, unpaid principal balance	140,000	0
With related allowance recorded, principal balance	135,000	0
Related allowance	5,000	0
With related allowance recorded, average recorded principal balance	112,000	429,000
Originated Loan [Member] | Retail Portfolio Segment [Member]
With no related allowance recorded, unpaid principal balance	1,660,000	1,819,000
With no related allowance recorded, principal balance	976,000	1,136,000
With no related allowance recorded, average recorded principal balance	1,105,000	1,122,000
With related allowance recorded, unpaid principal balance	851,000	1,390,000
With related allowance recorded, principal balance	772,000	1,257,000
Related allowance	238,000	665,000
With related allowance recorded, average recorded principal balance	899,000	1,044,000
Total unpaid principal balance	2,511,000	3,209,000
Total principal balance	1,748,000	2,393,000
Total average recorded principal balance	2,004,000	2,166,000
Originated Loan [Member] | Retail Portfolio Segment [Member] | Home Equity and Other [Member]
With no related allowance recorded, unpaid principal balance	607,000	693,000
With no related allowance recorded, principal balance	586,000	680,000
With no related allowance recorded, average recorded principal balance	691,000	526,000
With related allowance recorded, unpaid principal balance	442,000	1,225,000
With related allowance recorded, principal balance	431,000	1,147,000
Related allowance	194,000	652,000
With related allowance recorded, average recorded principal balance	600,000	922,000
Originated Loan [Member] | Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
With no related allowance recorded, unpaid principal balance	1,053,000	1,126,000
With no related allowance recorded, principal balance	390,000	456,000
With no related allowance recorded, average recorded principal balance	414,000	596,000
With related allowance recorded, unpaid principal balance	409,000	165,000
With related allowance recorded, principal balance	341,000	110,000
Related allowance	44,000	13,000
With related allowance recorded, average recorded principal balance	299,000	122,000
Acquired Loan [Member]
With no related allowance recorded, unpaid principal balance	4,518,000	5,938,000
With no related allowance recorded, principal balance	3,827,000	4,795,000
With no related allowance recorded, average recorded principal balance	4,340,000	5,504,000
With related allowance recorded, unpaid principal balance	1,415,000	0
With related allowance recorded, principal balance	1,337,000	0
Related allowance	310,000	0
With related allowance recorded, average recorded principal balance	594,000	185,000
Total unpaid principal balance	5,933,000	5,938,000
Total principal balance	5,164,000	4,795,000
Total average recorded principal balance	4,934,000	5,689,000
Acquired Loan [Member] | Commercial Portfolio Segment [Member]
With no related allowance recorded, unpaid principal balance	1,636,000	2,541,000
With no related allowance recorded, principal balance	1,617,000	2,135,000
With no related allowance recorded, average recorded principal balance	1,694,000	3,202,000
With related allowance recorded, unpaid principal balance	535,000	0
With related allowance recorded, principal balance	526,000	0
Related allowance	43,000	0
With related allowance recorded, average recorded principal balance	425,000	48,000
Total unpaid principal balance	2,171,000	2,541,000
Total principal balance	2,143,000	2,135,000
Total average recorded principal balance	2,119,000	3,250,000
Acquired Loan [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
With no related allowance recorded, unpaid principal balance	398,000	1,039,000
With no related allowance recorded, principal balance	398,000	1,021,000
With no related allowance recorded, average recorded principal balance	690,000	1,039,000
With related allowance recorded, unpaid principal balance	175,000	0
With related allowance recorded, principal balance	166,000	0
Related allowance	43,000	0
With related allowance recorded, average recorded principal balance	33,000	10,000
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
With no related allowance recorded, principal balance	0	0
With no related allowance recorded, average recorded principal balance	0	12,000
With related allowance recorded, unpaid principal balance	0	0
With related allowance recorded, principal balance	0	0
Related allowance	0	0
With related allowance recorded, average recorded principal balance	0	0
Acquired Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
With no related allowance recorded, unpaid principal balance	1,193,000	1,027,000
With no related allowance recorded, principal balance	1,193,000	659,000
With no related allowance recorded, average recorded principal balance	749,000	1,005,000
With related allowance recorded, unpaid principal balance	147,000	0
With related allowance recorded, principal balance	147,000	0
Related allowance	0	0
With related allowance recorded, average recorded principal balance	349,000	38,000
Acquired Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
With no related allowance recorded, unpaid principal balance	0	238,000
With no related allowance recorded, principal balance	0	237,000
With no related allowance recorded, average recorded principal balance	182,000	738,000
With related allowance recorded, unpaid principal balance	210,000	0
With related allowance recorded, principal balance	210,000	0
Related allowance	0	0
With related allowance recorded, average recorded principal balance	42,000	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	45,000	237,000
With no related allowance recorded, principal balance	26,000	218,000
With no related allowance recorded, average recorded principal balance	73,000	408,000
With related allowance recorded, unpaid principal balance	3,000	0
With related allowance recorded, principal balance	3,000	0
Related allowance	0	0
With related allowance recorded, average recorded principal balance	1,000	0
Acquired Loan [Member] | Retail Portfolio Segment [Member]
With no related allowance recorded, unpaid principal balance	2,882,000	3,397,000
With no related allowance recorded, principal balance	2,210,000	2,660,000
With no related allowance recorded, average recorded principal balance	2,646,000	2,302,000
With related allowance recorded, unpaid principal balance	880,000	0
With related allowance recorded, principal balance	811,000	0
Related allowance	267,000	0
With related allowance recorded, average recorded principal balance	169,000	137,000
Total unpaid principal balance	3,762,000	3,397,000
Total principal balance	3,021,000	2,660,000
Total average recorded principal balance	2,815,000	2,439,000
Acquired Loan [Member] | Retail Portfolio Segment [Member] | Home Equity and Other [Member]
With no related allowance recorded, unpaid principal balance	388,000	694,000
With no related allowance recorded, principal balance	361,000	507,000
With no related allowance recorded, average recorded principal balance	615,000	417,000
With related allowance recorded, unpaid principal balance	462,000	0
With related allowance recorded, principal balance	440,000	0
Related allowance	178,000	0
With related allowance recorded, average recorded principal balance	95,000	0
Acquired Loan [Member] | Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
With no related allowance recorded, unpaid principal balance	2,494,000	2,703,000
With no related allowance recorded, principal balance	1,849,000	2,153,000
With no related allowance recorded, average recorded principal balance	2,031,000	1,885,000
With related allowance recorded, unpaid principal balance	418,000	0
With related allowance recorded, principal balance	371,000	0
Related allowance	89,000	0
With related allowance recorded, average recorded principal balance	$ 74,000	$ 137,000