Note 3 - Loans and Allowance for Loan Losses - Impaired Loans (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Originated Loan [Member]
With no related allowance recorded, unpaid principal balance	$ 14,028,000		$ 14,028,000		$ 10,990,000
With no related allowance recorded, principal balance	13,425,000		13,425,000		10,306,000
With no related allowance recorded, average recorded principal balance	12,284,000	$ 3,248,000	11,624,000	$ 3,216,000
With related allowance recorded, unpaid principal balance	14,448,000		14,448,000		8,660,000
With related allowance recorded, principal balance	14,360,000		14,360,000		8,576,000
Related allowance	2,227,000		2,227,000		689,000
With related allowance recorded, average recorded principal balance	11,705,000	4,790,000	10,663,000	5,073,000
Total unpaid principal balance	28,476,000		28,476,000		19,650,000
Total principal balance	27,785,000		27,785,000		18,882,000
Total average recorded principal balance	23,989,000	8,038,000	22,287,000	8,289,000
Originated Loan [Member] | Commercial Portfolio Segment [Member]
With no related allowance recorded, unpaid principal balance	12,289,000		12,289,000		9,330,000
With no related allowance recorded, principal balance	12,280,000		12,280,000		9,330,000
With no related allowance recorded, average recorded principal balance	11,226,000	2,159,000	10,593,000	2,111,000
With related allowance recorded, unpaid principal balance	13,656,000		13,656,000		7,809,000
With related allowance recorded, principal balance	13,656,000		13,656,000		7,804,000
Related allowance	2,051,000		2,051,000		451,000
With related allowance recorded, average recorded principal balance	10,994,000	3,945,000	9,932,000	4,091,000
Total unpaid principal balance	25,945,000		25,945,000		17,139,000
Total principal balance	25,936,000		25,936,000		17,134,000
Total average recorded principal balance	22,220,000	6,104,000	20,525,000	6,202,000
Originated Loan [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
With no related allowance recorded, unpaid principal balance	10,007,000		10,007,000		8,604,000
With no related allowance recorded, principal balance	10,007,000		10,007,000		8,604,000
With no related allowance recorded, average recorded principal balance	9,792,000	373,000	9,396,000	308,000
With related allowance recorded, unpaid principal balance	13,656,000		13,656,000		5,011,000
With related allowance recorded, principal balance	13,656,000		13,656,000		5,011,000
Related allowance	2,051,000		2,051,000		83,000
With related allowance recorded, average recorded principal balance	9,581,000	2,089,000	8,058,000	2,389,000
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	88,000		88,000		94,000
With no related allowance recorded, principal balance	88,000		88,000		94,000
With no related allowance recorded, average recorded principal balance	90,000	50,000	91,000	45,000
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	2,059,000		2,059,000		632,000
With no related allowance recorded, principal balance	2,059,000		2,059,000		632,000
With no related allowance recorded, average recorded principal balance	1,281,000	1,453,000	1,064,000	1,453,000
With related allowance recorded, unpaid principal balance	0		0		2,658,000
With related allowance recorded, principal balance	0		0		2,658,000
Related allowance	0		0		363,000
With related allowance recorded, average recorded principal balance	1,348,000	1,713,000	1,785,000	1,606,000
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	135,000		135,000		0
With no related allowance recorded, principal balance	126,000		126,000		0
With no related allowance recorded, average recorded principal balance	63,000	283,000	42,000	305,000
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	65,000	143,000	89,000	96,000
Originated Loan [Member] | Retail Portfolio Segment [Member]
With no related allowance recorded, unpaid principal balance	1,739,000		1,739,000		1,660,000
With no related allowance recorded, principal balance	1,145,000		1,145,000		976,000
With no related allowance recorded, average recorded principal balance	1,058,000	1,089,000	1,031,000	1,105,000
With related allowance recorded, unpaid principal balance	792,000		792,000		851,000
With related allowance recorded, principal balance	704,000		704,000		772,000
Related allowance	176,000		176,000		238,000
With related allowance recorded, average recorded principal balance	711,000	845,000	731,000	982,000
Total unpaid principal balance	2,531,000		2,531,000		2,511,000
Total principal balance	1,849,000		1,849,000		1,748,000
Total average recorded principal balance	1,769,000	1,934,000	1,762,000	2,087,000
Originated Loan [Member] | Retail Portfolio Segment [Member] | Home Equity and Other [Member]
With no related allowance recorded, unpaid principal balance	829,000		829,000		607,000
With no related allowance recorded, principal balance	807,000		807,000		586,000
With no related allowance recorded, average recorded principal balance	707,000	684,000	667,000	683,000
With related allowance recorded, unpaid principal balance	386,000		386,000		442,000
With related allowance recorded, principal balance	373,000		373,000		431,000
Related allowance	158,000		158,000		194,000
With related allowance recorded, average recorded principal balance	377,000	494,000	395,000	712,000
Originated Loan [Member] | Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
With no related allowance recorded, unpaid principal balance	910,000		910,000		1,053,000
With no related allowance recorded, principal balance	338,000		338,000		390,000
With no related allowance recorded, average recorded principal balance	351,000	405,000	364,000	422,000
With related allowance recorded, unpaid principal balance	406,000		406,000		409,000
With related allowance recorded, principal balance	331,000		331,000		341,000
Related allowance	18,000		18,000		44,000
With related allowance recorded, average recorded principal balance	334,000	351,000	336,000	270,000
Acquired Loan [Member]
With no related allowance recorded, unpaid principal balance	4,705,000		4,705,000		4,518,000
With no related allowance recorded, principal balance	3,863,000		3,863,000		3,827,000
With no related allowance recorded, average recorded principal balance	3,928,000	4,377,000	3,894,000	4,517,000
With related allowance recorded, unpaid principal balance	791,000		791,000		1,415,000
With related allowance recorded, principal balance	764,000		764,000		1,337,000
Related allowance	222,000		222,000		310,000
With related allowance recorded, average recorded principal balance	689,000	816,000	905,000	545,000
Total unpaid principal balance	5,496,000		5,496,000		5,933,000
Total principal balance	4,627,000		4,627,000		5,164,000
Total average recorded principal balance	4,617,000	5,193,000	4,799,000	5,062,000
Acquired Loan [Member] | Commercial Portfolio Segment [Member]
With no related allowance recorded, unpaid principal balance	1,557,000		1,557,000		1,636,000
With no related allowance recorded, principal balance	1,501,000		1,501,000		1,617,000
With no related allowance recorded, average recorded principal balance	1,425,000	1,667,000	1,489,000	1,824,000
With related allowance recorded, unpaid principal balance	140,000		140,000		535,000
With related allowance recorded, principal balance	138,000		138,000		526,000
Related allowance	32,000		32,000		43,000
With related allowance recorded, average recorded principal balance	189,000	799,000	301,000	533,000
Total unpaid principal balance	1,697,000		1,697,000		2,171,000
Total principal balance	1,639,000		1,639,000		2,143,000
Total average recorded principal balance	1,614,000	2,466,000	1,790,000	2,357,000
Acquired Loan [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
With no related allowance recorded, unpaid principal balance	360,000		360,000		398,000
With no related allowance recorded, principal balance	353,000		353,000		398,000
With no related allowance recorded, average recorded principal balance	422,000	720,000	414,000	821,000
With related allowance recorded, unpaid principal balance	140,000		140,000		175,000
With related allowance recorded, principal balance	138,000		138,000		166,000
Related allowance	32,000		32,000		43,000
With related allowance recorded, average recorded principal balance	106,000	0	126,000	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	944,000		944,000		1,193,000
With no related allowance recorded, principal balance	916,000		916,000		1,193,000
With no related allowance recorded, average recorded principal balance	802,000	677,000	932,000	671,000
With related allowance recorded, unpaid principal balance	0		0		147,000
With related allowance recorded, principal balance	0		0		147,000
Related allowance	0		0		0
With related allowance recorded, average recorded principal balance	36,000	799,000	73,000	533,000
Acquired Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
With no related allowance recorded, unpaid principal balance	213,000		213,000		0
With no related allowance recorded, principal balance	211,000		211,000		0
With no related allowance recorded, average recorded principal balance	175,000	228,000	117,000	231,000
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	47,000	0	101,000	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	40,000		40,000		45,000
With no related allowance recorded, principal balance	21,000		21,000		26,000
With no related allowance recorded, average recorded principal balance	26,000	42,000	26,000	101,000
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	3,148,000		3,148,000		2,882,000
With no related allowance recorded, principal balance	2,362,000		2,362,000		2,210,000
With no related allowance recorded, average recorded principal balance	2,503,000	2,710,000	2,405,000	2,693,000
With related allowance recorded, unpaid principal balance	651,000		651,000		880,000
With related allowance recorded, principal balance	626,000		626,000		811,000
Related allowance	190,000		190,000		267,000
With related allowance recorded, average recorded principal balance	500,000	17,000	604,000	12,000
Total unpaid principal balance	3,799,000		3,799,000		3,762,000
Total principal balance	2,988,000		2,988,000		3,021,000
Total average recorded principal balance	3,003,000	2,727,000	3,009,000	2,705,000
Acquired Loan [Member] | Retail Portfolio Segment [Member] | Home Equity and Other [Member]
With no related allowance recorded, unpaid principal balance	686,000		686,000		388,000
With no related allowance recorded, principal balance	628,000		628,000		361,000
With no related allowance recorded, average recorded principal balance	653,000	710,000	555,000	642,000
With related allowance recorded, unpaid principal balance	243,000		243,000		462,000
With related allowance recorded, principal balance	241,000		241,000		440,000
Related allowance	107,000		107,000		178,000
With related allowance recorded, average recorded principal balance	195,000	17,000	277,000	12,000
Acquired Loan [Member] | Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
With no related allowance recorded, unpaid principal balance	2,462,000		2,462,000		2,494,000
With no related allowance recorded, principal balance	1,734,000		1,734,000		1,849,000
With no related allowance recorded, average recorded principal balance	1,850,000	2,000,000	1,850,000	2,051,000
With related allowance recorded, unpaid principal balance	408,000		408,000		418,000
With related allowance recorded, principal balance	385,000		385,000		371,000
Related allowance	83,000		83,000		$ 89,000
With related allowance recorded, average recorded principal balance	$ 305,000	$ 0	$ 327,000	$ 0