Note 3 - Loans and Allowance for Loan Losses - Impaired Loans (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Originated Loan [Member]
With no related allowance recorded, unpaid principal balance	$ 22,671,000		$ 22,671,000		$ 10,990,000
With no related allowance recorded, principal balance	22,072,000		22,072,000		10,306,000
With no related allowance recorded, average recorded principal balance	17,750,000	$ 2,459,000	14,237,000	$ 3,171,000
With related allowance recorded, unpaid principal balance	5,682,000		5,682,000		8,660,000
With related allowance recorded, principal balance	5,590,000		5,590,000		8,576,000
Related allowance	2,025,000		2,025,000		689,000
With related allowance recorded, average recorded principal balance	9,975,000	6,841,000	9,393,000	6,031,000
Total unpaid principal balance	28,353,000		28,353,000		19,650,000
Total principal balance	27,662,000		27,662,000		18,882,000
Total average recorded principal balance	27,725,000	9,300,000	23,630,000	9,202,000
Originated Loan [Member] | Commercial Portfolio Segment [Member]
With no related allowance recorded, unpaid principal balance	21,032,000		21,032,000		9,330,000
With no related allowance recorded, principal balance	21,032,000		21,032,000		9,330,000
With no related allowance recorded, average recorded principal balance	16,657,000	1,338,000	13,204,000	2,034,000
With related allowance recorded, unpaid principal balance	4,866,000		4,866,000		7,809,000
With related allowance recorded, principal balance	4,866,000		4,866,000		7,804,000
Related allowance	1,699,000		1,699,000		451,000
With related allowance recorded, average recorded principal balance	9,261,000	6,032,000	8,664,000	5,099,000
Total unpaid principal balance	25,898,000		25,898,000		17,139,000
Total principal balance	25,898,000		25,898,000		17,134,000
Total average recorded principal balance	25,918,000	7,370,000	21,868,000	7,133,000
Originated Loan [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
With no related allowance recorded, unpaid principal balance	20,280,000		20,280,000		8,604,000
With no related allowance recorded, principal balance	20,280,000		20,280,000		8,604,000
With no related allowance recorded, average recorded principal balance	15,144,000	732,000	12,117,000	469,000
With related allowance recorded, unpaid principal balance	3,333,000		3,333,000		5,011,000
With related allowance recorded, principal balance	3,333,000		3,333,000		5,011,000
Related allowance	699,000		699,000		83,000
With related allowance recorded, average recorded principal balance	8,494,000	3,572,000	6,876,000	3,067,000
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	87,000		87,000		94,000
With no related allowance recorded, principal balance	87,000		87,000		94,000
With no related allowance recorded, average recorded principal balance	88,000	98,000	90,000	58,000
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
Originated Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
With no related allowance recorded, unpaid principal balance	665,000		665,000		632,000
With no related allowance recorded, principal balance	665,000		665,000		632,000
With no related allowance recorded, average recorded principal balance	1,362,000	383,000	965,000	1,273,000
With related allowance recorded, unpaid principal balance	1,533,000		1,533,000		2,658,000
With related allowance recorded, principal balance	1,533,000		1,533,000		2,658,000
Related allowance	1,000,000		1,000,000		363,000
With related allowance recorded, average recorded principal balance	767,000	2,320,000	1,722,000	1,926,000
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	0	0	0
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		0		0
With no related allowance recorded, principal balance	0		0		0
With no related allowance recorded, average recorded principal balance	63,000	125,000	32,000	234,000
With related allowance recorded, unpaid principal balance	0		0		140,000
With related allowance recorded, principal balance	0		0		135,000
Related allowance	0		0		5,000
With related allowance recorded, average recorded principal balance	0	140,000	66,000	106,000
Originated Loan [Member] | Retail Portfolio Segment [Member]
With no related allowance recorded, unpaid principal balance	1,639,000		1,639,000		1,660,000
With no related allowance recorded, principal balance	1,040,000		1,040,000		976,000
With no related allowance recorded, average recorded principal balance	1,093,000	1,121,000	1,033,000	1,137,000
With related allowance recorded, unpaid principal balance	816,000		816,000		851,000
With related allowance recorded, principal balance	724,000		724,000		772,000
Related allowance	326,000		326,000		238,000
With related allowance recorded, average recorded principal balance	714,000	809,000	729,000	932,000
Total unpaid principal balance	2,455,000		2,455,000		2,511,000
Total principal balance	1,764,000		1,764,000		1,748,000
Total average recorded principal balance	1,807,000	1,930,000	1,762,000	2,069,000
Originated Loan [Member] | Retail Portfolio Segment [Member] | Home Equity and Other [Member]
With no related allowance recorded, unpaid principal balance	743,000		743,000		607,000
With no related allowance recorded, principal balance	720,000		720,000		586,000
With no related allowance recorded, average recorded principal balance	764,000	719,000	680,000	717,000
With related allowance recorded, unpaid principal balance	411,000		411,000		442,000
With related allowance recorded, principal balance	397,000		397,000		431,000
Related allowance	312,000		312,000		194,000
With related allowance recorded, average recorded principal balance	385,000	463,000	395,000	643,000
Originated Loan [Member] | Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
With no related allowance recorded, unpaid principal balance	896,000		896,000		1,053,000
With no related allowance recorded, principal balance	320,000		320,000		390,000
With no related allowance recorded, average recorded principal balance	329,000	402,000	353,000	420,000
With related allowance recorded, unpaid principal balance	405,000		405,000		409,000
With related allowance recorded, principal balance	327,000		327,000		341,000
Related allowance	14,000		14,000		44,000
With related allowance recorded, average recorded principal balance	329,000	346,000	334,000	289,000
Acquired Loan [Member]
With no related allowance recorded, unpaid principal balance	3,720,000		3,720,000		4,518,000
With no related allowance recorded, principal balance	2,832,000		2,832,000		3,827,000
With no related allowance recorded, average recorded principal balance	3,348,000	4,346,000	3,548,000	4,469,000
With related allowance recorded, unpaid principal balance	888,000		888,000		1,415,000
With related allowance recorded, principal balance	882,000		882,000		1,337,000
Related allowance	242,000		242,000		310,000
With related allowance recorded, average recorded principal balance	823,000	34,000	1,053,000	412,000
Total unpaid principal balance	4,608,000		4,608,000		5,933,000
Total principal balance	3,714,000		3,714,000		5,164,000
Total average recorded principal balance	4,171,000	4,380,000	4,601,000	4,881,000
Acquired Loan [Member] | Commercial Portfolio Segment [Member]
With no related allowance recorded, unpaid principal balance	677,000		677,000		1,636,000
With no related allowance recorded, principal balance	655,000		655,000		1,617,000
With no related allowance recorded, average recorded principal balance	1,078,000	1,495,000	1,273,000	1,714,000
With related allowance recorded, unpaid principal balance	235,000		235,000		535,000
With related allowance recorded, principal balance	233,000		233,000		526,000
Related allowance	35,000		35,000		43,000
With related allowance recorded, average recorded principal balance	186,000	0	345,000	400,000
Total unpaid principal balance	912,000		912,000		2,171,000
Total principal balance	888,000		888,000		2,143,000
Total average recorded principal balance	1,264,000	1,495,000	1,618,000	2,114,000
Acquired Loan [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
With no related allowance recorded, unpaid principal balance	307,000		307,000		398,000
With no related allowance recorded, principal balance	307,000		307,000		398,000
With no related allowance recorded, average recorded principal balance	330,000	648,000	363,000	763,000
With related allowance recorded, unpaid principal balance	134,000		134,000		175,000
With related allowance recorded, principal balance	132,000		132,000		166,000
Related allowance	30,000		30,000		43,000
With related allowance recorded, average recorded principal balance	135,000	0	146,000	0
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	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	0	0	0
Acquired Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
With no related allowance recorded, unpaid principal balance	126,000		126,000		1,193,000
With no related allowance recorded, principal balance	126,000		126,000		1,193,000
With no related allowance recorded, average recorded principal balance	521,000	588,000	768,000	638,000
With related allowance recorded, unpaid principal balance	101,000		101,000		147,000
With related allowance recorded, principal balance	101,000		101,000		147,000
Related allowance	5,000		5,000		0
With related allowance recorded, average recorded principal balance	51,000	0	98,000	400,000
Acquired Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
With no related allowance recorded, unpaid principal balance	209,000		209,000		0
With no related allowance recorded, principal balance	207,000		207,000		0
With no related allowance recorded, average recorded principal balance	209,000	221,000	120,000	228,000
With related allowance recorded, unpaid principal balance	0		0		210,000
With related allowance recorded, principal balance	0		0		210,000
Related allowance	0		0		0
With related allowance recorded, average recorded principal balance	0	0	100,000	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	35,000		35,000		45,000
With no related allowance recorded, principal balance	15,000		15,000		26,000
With no related allowance recorded, average recorded principal balance	18,000	38,000	22,000	85,000
With related allowance recorded, unpaid principal balance	0		0		3,000
With related allowance recorded, principal balance	0		0		3,000
Related allowance	0		0		0
With related allowance recorded, average recorded principal balance	0	0	1,000	0
Acquired Loan [Member] | Retail Portfolio Segment [Member]
With no related allowance recorded, unpaid principal balance	3,043,000		3,043,000		2,882,000
With no related allowance recorded, principal balance	2,177,000		2,177,000		2,210,000
With no related allowance recorded, average recorded principal balance	2,270,000	2,851,000	2,275,000	2,755,000
With related allowance recorded, unpaid principal balance	653,000		653,000		880,000
With related allowance recorded, principal balance	649,000		649,000		811,000
Related allowance	207,000		207,000		267,000
With related allowance recorded, average recorded principal balance	637,000	34,000	708,000	12,000
Total unpaid principal balance	3,696,000		3,696,000		3,762,000
Total principal balance	2,826,000		2,826,000		3,021,000
Total average recorded principal balance	2,907,000	2,885,000	2,983,000	2,767,000
Acquired Loan [Member] | Retail Portfolio Segment [Member] | Home Equity and Other [Member]
With no related allowance recorded, unpaid principal balance	577,000		577,000		388,000
With no related allowance recorded, principal balance	527,000		527,000		361,000
With no related allowance recorded, average recorded principal balance	578,000	778,000	522,000	678,000
With related allowance recorded, unpaid principal balance	247,000		247,000		462,000
With related allowance recorded, principal balance	245,000		245,000		440,000
Related allowance	120,000		120,000		178,000
With related allowance recorded, average recorded principal balance	243,000	34,000	306,000	12,000
Acquired Loan [Member] | Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
With no related allowance recorded, unpaid principal balance	2,466,000		2,466,000		2,494,000
With no related allowance recorded, principal balance	1,650,000		1,650,000		1,849,000
With no related allowance recorded, average recorded principal balance	1,692,000	2,073,000	1,753,000	2,077,000
With related allowance recorded, unpaid principal balance	406,000		406,000		418,000
With related allowance recorded, principal balance	404,000		404,000		371,000
Related allowance	87,000		87,000		$ 89,000
With related allowance recorded, average recorded principal balance	$ 394,000	$ 0	$ 402,000	$ 0