Note 6 - Allowance for Loan Losses - Allowance for Loan Losses and Recorded Investment in Loans, Evaluated for Impairment Excluding PCI Loans, by Loan Class (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Loans individually evaluated for impairment	$ 5,070	$ 13,170
Allowance for loans individually evaluated	1,452	2,558
Loans collectively evaluated for impairment	1,758,011	1,785,574
Allowance for loans collectively evaluated	16,815	16,718
Commercial Portfolio Segment [Member]
Loans individually evaluated for impairment	1,374	3,699
Allowance for loans individually evaluated	465	580
Loans collectively evaluated for impairment	1,049,381	1,058,468
Allowance for loans collectively evaluated	10,034	11,092
Commercial Portfolio Segment [Member] | Construction, Development and Other Land [Member]
Loans individually evaluated for impairment
Allowance for loans individually evaluated
Loans collectively evaluated for impairment	63,039	59,386
Allowance for loans collectively evaluated	417	830
Commercial Portfolio Segment [Member] | Commercial and Industrial [Member]
Loans individually evaluated for impairment		343
Allowance for loans individually evaluated		270
Loans collectively evaluated for impairment	104,863	91,845
Allowance for loans collectively evaluated	663	492
Commercial Portfolio Segment [Member] | Multi-family Residential [Member]
Loans individually evaluated for impairment	534
Allowance for loans individually evaluated	230
Loans collectively evaluated for impairment	106,478	125,202
Allowance for loans collectively evaluated	962	1,094
Commercial Portfolio Segment [Member] | Single Family Non-owner Occupied [Member]
Loans individually evaluated for impairment		770
Allowance for loans individually evaluated		62
Loans collectively evaluated for impairment	138,451	139,093
Allowance for loans collectively evaluated	1,442	1,914
Commercial Portfolio Segment [Member] | Non-farm, Non-residential [Member]
Loans individually evaluated for impairment	840	1,367
Allowance for loans individually evaluated	235	15
Loans collectively evaluated for impairment	609,100	611,477
Allowance for loans collectively evaluated	6,295	6,582
Commercial Portfolio Segment [Member] | Agricultural [Member]
Loans individually evaluated for impairment
Allowance for loans individually evaluated
Loans collectively evaluated for impairment	8,545	7,035
Allowance for loans collectively evaluated	85	51
Commercial Portfolio Segment [Member] | Farmland [Member]
Loans individually evaluated for impairment		1,219
Allowance for loans individually evaluated		233
Loans collectively evaluated for impairment	18,905	24,430
Allowance for loans collectively evaluated	170	129
Consumer Real Estate Portfolio Segment [Member]
Loans individually evaluated for impairment	3,696	9,471
Allowance for loans individually evaluated	987	1,978
Loans collectively evaluated for impairment	631,768	651,333
Allowance for loans collectively evaluated	5,745	4,832
Consumer Real Estate Portfolio Segment [Member] | Home Equity Lines [Member]
Loans individually evaluated for impairment	65
Allowance for loans individually evaluated	65
Loans collectively evaluated for impairment	103,668	115,807
Allowance for loans collectively evaluated	683	803
Consumer Real Estate Portfolio Segment [Member] | Single Family Owner Occupied [Member]
Loans individually evaluated for impairment	3,631	9,471
Allowance for loans individually evaluated	922	1,978
Loans collectively evaluated for impairment	509,929	496,348
Allowance for loans collectively evaluated	4,931	3,732
Consumer Real Estate Portfolio Segment [Member] | Owner Occupied Construction [Member]
Loans individually evaluated for impairment
Allowance for loans individually evaluated
Loans collectively evaluated for impairment	18,171	39,178
Allowance for loans collectively evaluated	131	297
Consumer and Other Portfolio Segment [Member]
Loans individually evaluated for impairment
Allowance for loans individually evaluated
Loans collectively evaluated for impairment	76,862	75,773
Allowance for loans collectively evaluated	1,036	794
Consumer and Other Portfolio Segment [Member] | Consumer Loans [Member]
Loans individually evaluated for impairment
Allowance for loans individually evaluated
Loans collectively evaluated for impairment	71,552	70,772
Allowance for loans collectively evaluated	1,036	794
Consumer and Other Portfolio Segment [Member] | Other Loan [Member]
Loans individually evaluated for impairment
Allowance for loans individually evaluated
Loans collectively evaluated for impairment	5,310	5,001
Allowance for loans collectively evaluated