Note 3 - Investment Securities (Tables)

12 Months Ended

Dec. 31, 2023

Notes Tables

Debt Securities, Available-for-Sale [Table Text Block]

			Gross		Gross
	Amortized		Unrealized		Unrealized			Fair
	Cost		Gains		Losses			Value
	(dollars in thousands)
December 31, 2023
Investment securities available-for-sale
Federal agency obligations	$	55,898	$	189	$	(10,761	)	$	45,326
Residential mortgage pass-through securities		462,004		620		(51,433	)		411,191
Commercial mortgage pass-through securities		25,240		-		(3,676	)		21,564
Obligations of U.S. states and political subdivisions​​		148,795		415		(16,505	)		132,705
Corporate bonds and notes		5,000		-		(27	)		4,973
Asset-backed securities		1,260		-		(22	)		1,238
Other securities		165		-		-			165
Total investment securities available-for-sale	$	698,362	$	1,224	$	(82,424	)	$	617,162

			Gross		Gross
	Amortized		Unrealized		Unrealized			Fair
	Cost		Gains		Losses			Value
	(dollars in thousands)
December 31, 2022
Investment securities available-for-sale
Federal agency obligations	$	54,889	$	-	$	(10,439	)	$	44,450
Residential mortgage pass-through securities		475,263		178		(57,863	)		417,578
Commercial mortgage pass-through securities		25,485		-		(4,381	)		21,104
Obligations of U.S. states and political subdivisions​​		157,247		111		(14,462	)		142,896
Corporate bonds and notes		7,000		-		(26	)		6,974
Asset-backed securities		1,673		-		(33	)		1,640
Other securities		242		-		-			242
Total investment securities available-for-sale	$	721,799	$	289	$	(87,204	)	$	634,884

Investments Classified by Contractual Maturity Date [Table Text Block]

	December 31, 2023
	Amortized		Fair
	Cost		Value
	(dollars in thousands)
Investment securities available-for-sale:
Due in one year or less	$	2,000	$	1,980
Due after one year through five years		6,389		6,379
Due after five years through ten years		1,851		1,857
Due after ten years		200,713		174,026
Residential mortgage pass-through securities		462,004		411,191
Commercial mortgage pass-through securities		25,240		21,564
Other securities		165		165
Total investment securities available-for-sale	$	698,362	$	617,162

Schedule of Realized Gain (Loss) [Table Text Block]

	Years Ended December 31,
	2023		2022		2021
	(dollars in thousands)
Proceeds	$	-	$	-	$	5,185
Gross gains on sale/redemption of investment securities	$	-	$	-	$	195
Gross losses on sale/redemption of investment securities		-		-		-
Net gains on sales/redemptions of investment securities​​		-		-		195
Tax provision on net gains		-		-		(48	)
Net gains on sale/redemption of investment securities, after tax​​	$	-	$	-	$	147

Unrealized Gain (Loss) on Investments [Table Text Block]

	December 31, 2023
	Total					Less than 12 Months					12 Months or Longer
	Fair		Unrealized			Fair		Unrealized			Fair		Unrealized
	Value		Losses			Value		Losses			Value		Losses
	(dollars in thousands)
Investment securities available-for-sale:
Federal agency obligation	$	40,779	$	(10,761	)	$	1,689	$	(65	)	$	39,090	$	(10,696	)
Residential mortgage pass-through securities		382,042		(51,433	)		4,138		(51	)		377,904		(51,382	)
Commercial mortgage pass-through securities		21,565		(3,676	)		-		-			21,565		(3,676	)
Obligations of U.S. states and political subdivisions		101,189		(16,505	)		1,340		(7	)		99,849		(16,498	)
Corporate bonds and notes		4,973		(27	)		2,993		(7	)		1,980		(20	)
Asset-backed securities		1,238		(22	)		-		-			1,238		(22	)
Total temporarily impaired securities	$	551,786	$	(82,424	)	$	10,160	$	(130	)	$	541,626	$	(82,294	)

	December 31, 2022
	Total					Less than 12 Months					12 Months or Longer
	Fair		Unrealized			Fair		Unrealized			Fair		Unrealized
	Value		Losses			Value		Losses			Value		Losses
	(dollars in thousands)
Investment securities available-for-sale:
Federal agency obligation	$	44,451	$	(10,439	)	$	20,517	$	(1,831	)	$	23,934	$	(8,608	)
Residential mortgage pass-through securities		403,039		(57,863	)		218,918		(13,869	)		184,121		(43,994	)
Commercial mortgage pass-through securities		21,105		(4,381	)		14,523		(2,304	)		6,582		(2,077	)
Obligations of U.S. states and political subdivisions		133,265		(14,462	)		47,446		(3,404	)		85,819		(11,058	)
Corporate bonds and notes		4,973		(26	)		4,973		(26	)		-		-
Asset-backed securities		1,640		(33	)		1,048		(16	)		592		(17	)
Total temporarily impaired securities	$	608,473	$	(87,204	)	$	307,425	$	(21,450	)	$	301,048	$	(65,754	)