Note 3 - Investment Securities (Tables)

12 Months Ended

Dec. 31, 2022

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, 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 securities available-for-sale	$	721,799	$	289	$	(87,204	)	$	634,884

			Gross		Gross
	Amortized		Unrealized		Unrealized			Fair
	Cost		Gains		Losses			Value
	(dollars in thousands)
December 31, 2021
Investment securities available-for-sale
Federal agency obligations	$	50,336	$	649	$	(625	)	$	50,360
Residential mortgage pass-through securities		317,111		1,868		(2,884	)		316,095
Commercial mortgage pass-through securities		10,814		118		(463	)		10,469
Obligations of U.S. states and political subdivisions​​		145,045		1,562		(982	)		145,625
Corporate bonds and notes		8,968		81		-			9,049
Asset-backed securities		2,563		3		(2	)		2,564
Certificates of deposit		150		-		-			150
Other securities		195		-		-			195
Total securities available-for-sale	$	535,182	$	4,281	$	(4,956	)	$	534,507

Investments Classified by Contractual Maturity Date [Table Text Block]

	December 31, 2022
	Amortized		Fair
	Cost		Value
	(dollars in thousands)
Investment securities available-for-sale:
Due in one year or less	$	5,453	$	5,451
Due after one year through five years		4,106		4,082
Due after five years through ten years		2,247		2,244
Due after ten years		209,003		184,183
Residential mortgage pass-through securities		475,263		417,578
Commercial mortgage pass-through securities		25,485		21,104
Other securities		242		242
Total securities available-for-sale	$	721,799	$	634,884

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

	Years Ended December 31,
	2022		2021			2020
	(dollars in thousands)
Proceeds	$	-	$	5,185		$	19,624
Gross gains on sale/redemption of investment securities	$	-	$	195		$	29
Gross losses on sale/redemption of investment securities		-		-			-
Net gains on sales/redemptions of investment securities​​		-		195			29
Tax provision on net gains		-		(48	)		(6	)
Net gains on sale/redemption of investment securities, after tax​​	$	-	$	147		$	23

Schedule of Unrealized Loss on Investments [Table Text Block]

	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	)

	December 31, 2021
	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	$	28,974	$	(625	)	$	28,974	$	(625	)	$	-	$	-
Residential mortgage pass-through securities		246,396		(2,884	)		214,701		(2,111	)		31,695		(773	)
Commercial mortgage pass-through securities		8,370		(463	)		4,682		(75	)		3,688		(388	)
Obligations of U.S. states and political subdivisions		89,473		(982	)		89,473		(982	)		-		-
Asset-backed securities		802		(2	)		802		(2	)		-		-
Total temporarily impaired securities	$	374,015	$	(4,956	)	$	338,632	$	(3,795	)	$	35,383	$	(1,161	)