Note 3 - Debt and Equity Securities (Tables)

6 Months Ended

Jun. 30, 2023

Notes Tables

Marketable Securities [Table Text Block]

	June 30, 2023
	Securities Available-For-Sale
	In Thousands
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Market Value
U.S. Treasury and other U.S. government agencies	$	7,370		—		830		6,540
U.S. Government-sponsored enterprises (GSEs)		177,249		—		27,891		149,358
Mortgage-backed securities		485,679		2		71,139		414,542
Asset-backed securities		45,048		30		2,192		42,886
Corporate bonds		2,500		—		119		2,381
Obligations of states and political subdivisions		219,152		—		35,018		184,134
	$	936,998		32		137,189		799,841

	December 31, 2022
	Securities Available-For-Sale
	In Thousands
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Market Value
U.S. Treasury and other U.S. government agencies	$	7,353		—		856		6,497
U.S. Government-sponsored enterprises (GSEs)		177,261		—		32,049		145,212
Mortgage-backed securities		518,727		1		74,290		444,438
Asset-backed securities		47,538		—		2,288		45,250
Corporate bonds		2,500		—		97		2,403
Obligations of states and political subdivisions		218,936		—		39,924		179,012
	$	972,315		1		149,504		822,812

Investments Classified by Contractual Maturity Date [Table Text Block]

	Available-For-Sale
	In Thousands
	Amortized Cost		Estimated Market Value
Due in one year or less	$	5,023	$	4,985
Due after one year through five years		99,690		88,969
Due after five years through ten years		267,253		226,090
Due after ten years		565,032		479,797
	$	936,998	$	799,841

Schedule of Unrealized Loss on Investments [Table Text Block]

	In Thousands, Except Number of Securities
	Less than 12 Months						12 Months or More						Total
June 30, 2023	Fair Value		Unrealized Losses		Number of Securities Included		Fair Value		Unrealized Losses		Number of Securities Included		Fair Value		Unrealized Losses
Available-for-Sale Securities:
U.S. Treasury and other U.S. government agencies	$	—	$	—		—	$	6,540	$	830		3	$	6,540	$	830
U.S. Government-sponsored enterprises (GSEs)		—		—		—		149,358		27,891		58		149,358		27,891
Mortgage-backed securities		604		12		5		413,424		71,127		233		414,028		71,139
Asset-backed securities		13,653		757		6		24,238		1,435		22		37,891		2,192
Corporate bonds		—		—		—		2,381		119		1		2,381		119
Obligations of states and political subdivisions		8,054		131		4		176,080		34,887		202		184,134		35,018
	$	22,311	$	900		15	$	772,021	$	136,289		519	$	794,332	$	137,189

	In Thousands, Except Number of Securities
	Less than 12 Months						12 Months or More						Total
December 31, 2022	Fair Value		Unrealized Losses		Number of Securities Included		Fair Value		Unrealized Losses		Number of Securities Included		Fair Value		Unrealized Losses
Available-for-Sale Securities:
U.S. Treasury and other U.S. government agencies	$	—	$	—		—	$	6,497	$	856		—		6,497	$	856
U.S. Government-sponsored enterprises (GSEs)		9,747		872		4		135,465		31,177		54		145,212		32,049
Mortgage-backed securities		148,441		14,601		113		295,431		59,689		136		443,872		74,290
Asset-backed securities		35,276		1607		21		9,974		681		11		45,250		2,288
Corporate bonds		2,403		97		1		—		—		—		2,403		97
Obligations of states and political subdivisions		58,567		6,056		76		120,445		33,868		128		179,012		39,924
	$	254,434	$	23,233		215	$	567,812	$	126,271		332	$	822,246	$	149,504