Note 3 - Loans and Allowance for Loan Losses - Impaired Loans (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Originated Loan [Member]
With no related allowance recorded, unpaid principal balance	$ 5,382,000		$ 4,915,000
With no related allowance recorded, principal balance	4,616,000		3,150,000
With no related allowance recorded, average recorded principal balance	3,883,000	$ 2,883,000
With related allowance recorded, unpaid principal balance	5,405,000		5,837,000
With related allowance recorded, principal balance	4,804,000		5,637,000
Related allowance	863,000		1,867,000
With related allowance recorded, average recorded principal balance	5,220,000	10,913,000
Total unpaid principal balance	10,787,000		10,752,000
Total principal balance	9,420,000		8,787,000
Total average recorded principal balance	9,103,000	13,796,000
Originated Loan [Member] | Commercial Portfolio Segment [Member]
With no related allowance recorded, unpaid principal balance	3,508,000		3,096,000
With no related allowance recorded, principal balance	3,446,000		2,014,000
With no related allowance recorded, average recorded principal balance	2,730,000	1,987,000
With related allowance recorded, unpaid principal balance	4,485,000		4,447,000
With related allowance recorded, principal balance	3,952,000		4,380,000
Related allowance	547,000		1,202,000
With related allowance recorded, average recorded principal balance	4,165,000	10,079,000
Total unpaid principal balance	7,993,000		7,543,000
Total principal balance	7,398,000		6,394,000
Total average recorded principal balance	6,895,000	12,066,000
Originated Loan [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
With no related allowance recorded, unpaid principal balance	234,000		765,000
With no related allowance recorded, principal balance	234,000		178,000
With no related allowance recorded, average recorded principal balance	206,000	1,589,000
With related allowance recorded, unpaid principal balance	2,623,000		3,038,000
With related allowance recorded, principal balance	2,133,000		2,989,000
Related allowance	304,000		963,000
With related allowance recorded, average recorded principal balance	2,561,000	2,690,000
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	0		454,000
With no related allowance recorded, principal balance	0		35,000
With no related allowance recorded, average recorded principal balance	17,000	88,000
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	749,000
Originated Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Owner Occupied Loan [Member]
With no related allowance recorded, unpaid principal balance	2,937,000		1,528,000
With no related allowance recorded, principal balance	2,875,000		1,452,000
With no related allowance recorded, average recorded principal balance	2,164,000	113,000
With related allowance recorded, unpaid principal balance	1,717,000		1,409,000
With related allowance recorded, principal balance	1,674,000		1,391,000
Related allowance	226,000		239,000
With related allowance recorded, average recorded principal balance	1,532,000	1,144,000
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	0
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	4,745,000
Originated Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Multi Family and Residential Rental Loan [Member]
With no related allowance recorded, unpaid principal balance	337,000		349,000
With no related allowance recorded, principal balance	337,000		349,000
With no related allowance recorded, average recorded principal balance	343,000	197,000
With related allowance recorded, unpaid principal balance	145,000		0
With related allowance recorded, principal balance	145,000		0
Related allowance	17,000		0
With related allowance recorded, average recorded principal balance	72,000	751,000
Originated Loan [Member] | Retail Portfolio Segment [Member]
With no related allowance recorded, unpaid principal balance	1,874,000		1,819,000
With no related allowance recorded, principal balance	1,170,000		1,136,000
With no related allowance recorded, average recorded principal balance	1,153,000	896,000
With related allowance recorded, unpaid principal balance	920,000		1,390,000
With related allowance recorded, principal balance	852,000		1,257,000
Related allowance	316,000		665,000
With related allowance recorded, average recorded principal balance	1,055,000	834,000
Total unpaid principal balance	2,794,000		3,209,000
Total principal balance	2,022,000		2,393,000
Total average recorded principal balance	2,208,000	1,730,000
Originated Loan [Member] | Retail Portfolio Segment [Member] | Home Equity and Other [Member]
With no related allowance recorded, unpaid principal balance	768,000		693,000
With no related allowance recorded, principal balance	751,000		680,000
With no related allowance recorded, average recorded principal balance	716,000	247,000
With related allowance recorded, unpaid principal balance	508,000		1,225,000
With related allowance recorded, principal balance	498,000		1,147,000
Related allowance	258,000		652,000
With related allowance recorded, average recorded principal balance	823,000	697,000
Originated Loan [Member] | Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
With no related allowance recorded, unpaid principal balance	1,106,000		1,126,000
With no related allowance recorded, principal balance	419,000		456,000
With no related allowance recorded, average recorded principal balance	437,000	649,000
With related allowance recorded, unpaid principal balance	412,000		165,000
With related allowance recorded, principal balance	354,000		110,000
Related allowance	58,000		13,000
With related allowance recorded, average recorded principal balance	232,000	137,000
Acquired Loan [Member]
With no related allowance recorded, unpaid principal balance	5,423,000		5,938,000
With no related allowance recorded, principal balance	4,380,000		4,795,000
With no related allowance recorded, average recorded principal balance	4,588,000	4,952,000
With related allowance recorded, unpaid principal balance	1,597,000		0
With related allowance recorded, principal balance	1,597,000		0
Related allowance	307,000		0
With related allowance recorded, average recorded principal balance	799,000	239,000
Total unpaid principal balance	7,020,000		5,938,000
Total principal balance	5,977,000		4,795,000
Total average recorded principal balance	5,387,000	5,191,000
Acquired Loan [Member] | Commercial Portfolio Segment [Member]
With no related allowance recorded, unpaid principal balance	2,147,000		2,541,000
With no related allowance recorded, principal balance	1,724,000		2,135,000
With no related allowance recorded, average recorded principal balance	1,930,000	2,954,000
With related allowance recorded, unpaid principal balance	1,597,000		0
With related allowance recorded, principal balance	1,597,000		0
Related allowance	307,000		0
With related allowance recorded, average recorded principal balance	799,000	67,000
Total unpaid principal balance	3,744,000		2,541,000
Total principal balance	3,321,000		2,135,000
Total average recorded principal balance	2,729,000	3,021,000
Acquired Loan [Member] | Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
With no related allowance recorded, unpaid principal balance	743,000		1,039,000
With no related allowance recorded, principal balance	733,000		1,021,000
With no related allowance recorded, average recorded principal balance	877,000	892,000
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	19,000
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	0
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	1,110,000		1,027,000
With no related allowance recorded, principal balance	715,000		659,000
With no related allowance recorded, average recorded principal balance	687,000	1,151,000
With related allowance recorded, unpaid principal balance	1,597,000		0
With related allowance recorded, principal balance	1,597,000		0
Related allowance	307,000		0
With related allowance recorded, average recorded principal balance	799,000	48,000
Acquired Loan [Member] | Commercial Portfolio Segment [Member] | Real Estate Non Owner Occupied Loan [Member]
With no related allowance recorded, unpaid principal balance	232,000		238,000
With no related allowance recorded, principal balance	232,000		237,000
With no related allowance recorded, average recorded principal balance	235,000	751,000
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 Multi Family and Residential Rental Loan [Member]
With no related allowance recorded, unpaid principal balance	62,000		237,000
With no related allowance recorded, principal balance	44,000		218,000
With no related allowance recorded, average recorded principal balance	131,000	160,000
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] | Retail Portfolio Segment [Member]
With no related allowance recorded, unpaid principal balance	3,276,000		3,397,000
With no related allowance recorded, principal balance	2,656,000		2,660,000
With no related allowance recorded, average recorded principal balance	2,658,000	1,998,000
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	172,000
Total unpaid principal balance	3,276,000		3,397,000
Total principal balance	2,656,000		2,660,000
Total average recorded principal balance	2,658,000	2,170,000
Acquired Loan [Member] | Retail Portfolio Segment [Member] | Home Equity and Other [Member]
With no related allowance recorded, unpaid principal balance	690,000		694,000
With no related allowance recorded, principal balance	649,000		507,000
With no related allowance recorded, average recorded principal balance	578,000	336,000
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] | Retail Portfolio Segment [Member] | One to Four Family Mortgages [Member]
With no related allowance recorded, unpaid principal balance	2,586,000		2,703,000
With no related allowance recorded, principal balance	2,007,000		2,153,000
With no related allowance recorded, average recorded principal balance	2,080,000	1,662,000
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	$ 172,000