Note 4 - Investment Securities - Expected Maturities (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Less than one year, Available for sale, Amortized Cost	$ 132,278	$ 53,256
Less than one year, Available for sale, Estimated Fair Value	132,236	53,243
More than one year to five years, Available for sale, Amortized Cost	81,753	73,970
Available for sale, Estimated Fair Value, More than one year to five years	74,709	68,471
More than five years to ten years, Available for sale, Amortized Cost	148,490	142,849
More than five years to ten years, Available for sale, Estimated Fair Value	127,650	122,326
More than ten years, Available for sale, Amortized Cost	28,953	18,013
More than ten years, Available for sale, Estimated Fair Value	19,783	12,790
Available for sale, amortized cost	391,474	288,088
Available for sale	354,378	256,830
Less than one year, Held to Maturity, Amortized Cost	0	501
Less than one year, Held to maturity, Estimated Fair Value	0	498
More than one year to five years, Held to maturity, Amortized Cost	502	502
More than one year to five years, Held to Maturity, Estimated Fair Value	499	509
More than five years to ten years, Held to maturity Amortized Cost	2,338	1,739
More than five years to ten years, Held to maturity Estimated Fair Value	2,085	1,692
More than ten years, Held to Maturity, Amortized Cost	2,374	2,987
More than ten years, Held to Maturity, Estimated Fair Value	2,166	2,864
Held to maturity (fair value of $4,750 and $5,563 at September 30, 2023 and December 31, 2022, respectively)	5,214	5,729
Securities held to maturity, fair value	4,750	5,563
US Government Agencies Debt Securities [Member]
Less than one year, Available for sale, Amortized Cost	0	0
Less than one year, Available for sale, Estimated Fair Value	0	0
More than one year to five years, Available for sale, Amortized Cost	8,694	5,012
Available for sale, Estimated Fair Value, More than one year to five years	7,894	4,495
More than five years to ten years, Available for sale, Amortized Cost	0	0
More than five years to ten years, Available for sale, Estimated Fair Value	0	0
More than ten years, Available for sale, Amortized Cost	0	0
More than ten years, Available for sale, Estimated Fair Value	0	0
Available for sale, amortized cost	8,694	5,012
Available for sale	7,894	4,495
Small Business Administration Agency Securities [Member]
Less than one year, Available for sale, Amortized Cost	0	0
Less than one year, Available for sale, Estimated Fair Value	0	0
More than one year to five years, Available for sale, Amortized Cost	2,387	2,634
Available for sale, Estimated Fair Value, More than one year to five years	2,115	2,411
More than five years to ten years, Available for sale, Amortized Cost	5,146	0
More than five years to ten years, Available for sale, Estimated Fair Value	5,146	0
More than ten years, Available for sale, Amortized Cost	0	0
More than ten years, Available for sale, Estimated Fair Value	0	0
Available for sale, amortized cost	7,533	2,634
Available for sale	7,261	2,411
Residential Mortgage-Backed Securities [Member]
Less than one year, Available for sale, Amortized Cost	0	0
Less than one year, Available for sale, Estimated Fair Value	0	0
More than one year to five years, Available for sale, Amortized Cost	11,546	13,013
Available for sale, Estimated Fair Value, More than one year to five years	10,028	11,598
More than five years to ten years, Available for sale, Amortized Cost	20,114	29,114
More than five years to ten years, Available for sale, Estimated Fair Value	16,164	24,361
More than ten years, Available for sale, Amortized Cost	9,841	2,682
More than ten years, Available for sale, Estimated Fair Value	7,245	2,098
Available for sale, amortized cost	41,501	44,809
Available for sale	33,437	38,057
Residential Collateralized Mortgage Obligations [Member]
Less than one year, Available for sale, Amortized Cost	0	0
Less than one year, Available for sale, Estimated Fair Value	0	0
More than one year to five years, Available for sale, Amortized Cost	23,737	20,687
Available for sale, Estimated Fair Value, More than one year to five years	22,217	19,646
More than five years to ten years, Available for sale, Amortized Cost	58,783	62,072
More than five years to ten years, Available for sale, Estimated Fair Value	46,416	50,257
More than ten years, Available for sale, Amortized Cost	3,823	0
More than ten years, Available for sale, Estimated Fair Value	2,566	0
Available for sale, amortized cost	86,343	82,759
Available for sale	71,199	69,903
Commercial Collateralized Mortgage Obligations [Member]
Less than one year, Available for sale, Amortized Cost	3,173	0
Less than one year, Available for sale, Estimated Fair Value	3,163	0
More than one year to five years, Available for sale, Amortized Cost	22,470	16,382
Available for sale, Estimated Fair Value, More than one year to five years	20,230	14,644
More than five years to ten years, Available for sale, Amortized Cost	45,194	28,209
More than five years to ten years, Available for sale, Estimated Fair Value	44,102	27,046
More than ten years, Available for sale, Amortized Cost	0	0
More than ten years, Available for sale, Estimated Fair Value	0	0
Available for sale, amortized cost	70,837	44,591
Available for sale	67,495	41,690
Commercial Paper [Member]
Less than one year, Available for sale, Amortized Cost	129,105	49,551
Less than one year, Available for sale, Estimated Fair Value	129,073	49,537
More than one year to five years, Available for sale, Amortized Cost	0	0
Available for sale, Estimated Fair Value, More than one year to five years	0	0
More than five years to ten years, Available for sale, Amortized Cost	0	0
More than five years to ten years, Available for sale, Estimated Fair Value	0	0
More than ten years, Available for sale, Amortized Cost	0	0
More than ten years, Available for sale, Estimated Fair Value	0	0
Available for sale, amortized cost	129,105	49,551
Available for sale	129,073	49,537
Corporate Debt Securities [Member]
Less than one year, Available for sale, Amortized Cost	0	3,705
Less than one year, Available for sale, Estimated Fair Value	0	3,706
More than one year to five years, Available for sale, Amortized Cost	12,919	11,355
Available for sale, Estimated Fair Value, More than one year to five years	12,225	10,806
More than five years to ten years, Available for sale, Amortized Cost	19,253	23,454
More than five years to ten years, Available for sale, Estimated Fair Value	15,822	20,662
More than ten years, Available for sale, Amortized Cost	2,645	2,662
More than ten years, Available for sale, Estimated Fair Value	1,759	1,838
Available for sale, amortized cost	34,817	41,176
Available for sale	29,806	37,012
Municipal Bonds [Member]
Less than one year, Available for sale, Amortized Cost	0	0
Less than one year, Available for sale, Estimated Fair Value	0	0
More than one year to five years, Available for sale, Amortized Cost	0	0
Available for sale, Estimated Fair Value, More than one year to five years	0	0
More than five years to ten years, Available for sale, Amortized Cost	0	0
More than five years to ten years, Available for sale, Estimated Fair Value	0	0
More than ten years, Available for sale, Amortized Cost	12,644	12,669
More than ten years, Available for sale, Estimated Fair Value	8,213	8,854
Available for sale, amortized cost	12,644	12,669
Available for sale	8,213	8,854
Less than one year, Held to Maturity, Amortized Cost	0	0
Less than one year, Held to maturity, Estimated Fair Value	0	0
More than one year to five years, Held to maturity, Amortized Cost	0	0
More than one year to five years, Held to Maturity, Estimated Fair Value	0	0
More than five years to ten years, Held to maturity Amortized Cost	2,338	1,739
More than five years to ten years, Held to maturity Estimated Fair Value	2,085	1,692
More than ten years, Held to Maturity, Amortized Cost	2,374	2,987
More than ten years, Held to Maturity, Estimated Fair Value	2,166	2,864
Held to maturity (fair value of $4,750 and $5,563 at September 30, 2023 and December 31, 2022, respectively)	4,712	4,726
Securities held to maturity, fair value	4,251	4,556
Taxable Municipal Bonds [Member]
Less than one year, Held to Maturity, Amortized Cost	0	501
Less than one year, Held to maturity, Estimated Fair Value	0	498
More than one year to five years, Held to maturity, Amortized Cost	502	502
More than one year to five years, Held to Maturity, Estimated Fair Value	499	509
More than five years to ten years, Held to maturity Amortized Cost	0	0
More than five years to ten years, Held to maturity Estimated Fair Value	0	0
More than ten years, Held to Maturity, Amortized Cost	0	0
More than ten years, Held to Maturity, Estimated Fair Value	0	0
Held to maturity (fair value of $4,750 and $5,563 at September 30, 2023 and December 31, 2022, respectively)	502	1,003
Securities held to maturity, fair value	$ 499	1,007
Commercial Mortgage-Backed Securities [Member]
Less than one year, Available for sale, Amortized Cost		0
Less than one year, Available for sale, Estimated Fair Value		0
More than one year to five years, Available for sale, Amortized Cost		4,887
Available for sale, Estimated Fair Value, More than one year to five years		4,871
More than five years to ten years, Available for sale, Amortized Cost		0
More than five years to ten years, Available for sale, Estimated Fair Value		0
More than ten years, Available for sale, Amortized Cost		0
More than ten years, Available for sale, Estimated Fair Value		0
Available for sale, amortized cost		4,887
Available for sale		$ 4,871