Note 3 - Loans and Allowance for Loan Losses - Impaired Loans (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
With no related allowance recorded, unpaid principal balance	$ 20,453,000		$ 20,453,000		$ 26,892,000
With no related allowance recorded, principal balance	19,102,000		19,102,000		24,738,000
With no related allowance recorded, average recorded principal balance	18,958,000	$ 15,506,000	20,892,000	$ 15,459,000
With related allowance recorded, unpaid principal balance	4,326,000		4,326,000		2,266,000
With related allowance recorded, principal balance	4,307,000		4,307,000		2,220,000
Related allowance	765,000		765,000		551,000
With related allowance recorded, average recorded principal balance	4,703,000	2,667,000	3,387,000	2,870,000
Total unpaid principal balance	24,779,000		24,779,000		29,158,000
Total principal balance	23,409,000		23,409,000		26,958,000
Total average recorded principal balance	23,661,000	18,173,000	24,279,000	18,329,000
Commercial Portfolio Segment [Member]
With no related allowance recorded, unpaid principal balance	15,666,000		15,666,000		21,365,000
With no related allowance recorded, principal balance	15,609,000		15,609,000		21,176,000
With no related allowance recorded, average recorded principal balance	15,479,000	11,696,000	17,396,000	11,771,000
With related allowance recorded, unpaid principal balance	3,728,000		3,728,000		1,268,000
With related allowance recorded, principal balance	3,728,000		3,728,000		1,239,000
Related allowance	544,000		544,000		138,000
With related allowance recorded, average recorded principal balance	4,034,000	1,544,000	2,586,000	1,846,000
Total unpaid principal balance	19,394,000		19,394,000		22,633,000
Total principal balance	19,337,000		19,337,000		22,415,000
Total average recorded principal balance	19,513,000	13,240,000	19,982,000	13,617,000
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
With no related allowance recorded, unpaid principal balance	2,900,000		2,900,000		6,242,000
With no related allowance recorded, principal balance	2,843,000		2,843,000		6,242,000
With no related allowance recorded, average recorded principal balance	2,759,000	7,416,000	3,836,000	8,282,000
With related allowance recorded, unpaid principal balance	2,802,000		2,802,000		343,000
With related allowance recorded, principal balance	2,802,000		2,802,000		343,000
Related allowance	449,000		449,000		53,000
With related allowance recorded, average recorded principal balance	2,888,000	940,000	1,617,000	1,128,000
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	326,000	0	234,000
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	96,000
Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
With no related allowance recorded, unpaid principal balance	12,674,000		12,674,000		14,782,000
With no related allowance recorded, principal balance	12,674,000		12,674,000		14,593,000
With no related allowance recorded, average recorded principal balance	12,674,000	3,645,000	13,374,000	3,053,000
With related allowance recorded, unpaid principal balance	775,000		775,000		763,000
With related allowance recorded, principal balance	775,000		775,000		734,000
Related allowance	89,000		89,000		77,000
With related allowance recorded, average recorded principal balance	994,000	436,000	813,000	538,000
Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
With no related allowance recorded, unpaid principal balance	0		0		341,000
With no related allowance recorded, principal balance	0		0		341,000
With no related allowance recorded, average recorded principal balance	0	309,000	163,000	199,000
With related allowance recorded, unpaid principal balance	151,000		151,000		162,000
With related allowance recorded, principal balance	151,000		151,000		162,000
Related allowance	6,000		6,000		8,000
With related allowance recorded, average recorded principal balance	152,000	168,000	156,000	84,000
Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
With no related allowance recorded, unpaid principal balance	92,000		92,000		0
With no related allowance recorded, principal balance	92,000		92,000		0
With no related allowance recorded, average recorded principal balance	46,000	0	23,000	3,000
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
Retail Portfolio Segment [Member]
With no related allowance recorded, unpaid principal balance	4,787,000		4,787,000		5,527,000
With no related allowance recorded, principal balance	3,493,000		3,493,000		3,562,000
With no related allowance recorded, average recorded principal balance	3,479,000	3,810,000	3,496,000	3,688,000
With related allowance recorded, unpaid principal balance	598,000		598,000		998,000
With related allowance recorded, principal balance	579,000		579,000		981,000
Related allowance	221,000		221,000		413,000
With related allowance recorded, average recorded principal balance	669,000	1,123,000	801,000	1,024,000
Total unpaid principal balance	5,385,000		5,385,000		6,525,000
Total principal balance	4,072,000		4,072,000		4,543,000
Total average recorded principal balance	4,148,000	4,933,000	4,297,000	4,712,000
Retail Portfolio Segment [Member] | Home Equity and Other [Member]
With no related allowance recorded, unpaid principal balance	1,291,000		1,291,000		1,072,000
With no related allowance recorded, principal balance	1,208,000		1,208,000		987,000
With no related allowance recorded, average recorded principal balance	1,223,000	1,305,000	1,093,000	1,273,000
With related allowance recorded, unpaid principal balance	182,000		182,000		300,000
With related allowance recorded, principal balance	163,000		163,000		283,000
Related allowance	142,000		142,000		241,000
With related allowance recorded, average recorded principal balance	197,000	470,000	232,000	455,000
Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
With no related allowance recorded, unpaid principal balance	3,496,000		3,496,000		4,455,000
With no related allowance recorded, principal balance	2,285,000		2,285,000		2,575,000
With no related allowance recorded, average recorded principal balance	2,256,000	2,505,000	2,403,000	2,415,000
With related allowance recorded, unpaid principal balance	416,000		416,000		698,000
With related allowance recorded, principal balance	416,000		416,000		698,000
Related allowance	79,000		79,000		$ 172,000
With related allowance recorded, average recorded principal balance	$ 472,000	$ 653,000	$ 569,000	$ 569,000