Investment Securities (Tables)

6 Months Ended

Jun. 30, 2023

Investments, Debt and Equity Securities [Abstract]

Available for Sale and Held for Maturity Securities

The amortized cost, gross unrealized gains and losses and estimated fair values for available-for-sale and held-to-maturity securities by major security type at June 30, 2023 and December 31, 2022 were as follows (in thousands):

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized (Losses)			Fair Value
June 30, 2023
Available-for-sale:
U.S. Treasury securities and obligations of U.S. government corporations and agencies	$	246,712	$	—	$	(31,558	)	$	215,154
Obligations of states and political subdivisions		338,377		61		(56,422	)		282,016
Mortgage-backed securities: GSE residential		713,394		1		(119,647	)		593,748
Other securities		79,320		—		(5,905	)		73,415
Total available-for-sale	$	1,377,803	$	62	$	(213,532	)	$	1,164,333
Held-to-maturity:
Other investments	$	2,971	$	—	$	—		$	2,971
Total held-to-maturity	$	2,971	$	—	$	—		$	2,971
December 31, 2022
Available-for-sale:
U.S. Treasury securities and obligations of U.S. government corporations and agencies	$	252,934	$	—	$	(32,407	)	$	220,527
Obligations of states and political subdivisions		347,409		134		(59,845	)		287,698
Mortgage-backed securities: GSE residential		744,636		3		(116,759	)		627,880
Other securities		87,393		6		(4,519	)		82,880
Total available-for-sale	$	1,432,372	$	143	$	(213,530	)	$	1,218,985
Held-to-maturity:
Other investments	$	2,954	$	—	$	—		$	2,954
Total held-to-maturity	$	2,954	$	—	$	—		$	2,954

Realized Gains and Losses From Sale of Securities

Realized gains and losses resulting from sales of securities were as follows during the three and six months ended June 30, 2023 and 2022 (in thousands):

	Three months June 30,					Six months June 30,
	2023			2022		2023			2022
Gross gains	$	—		$	2	$	6		$	2
Gross losses		(6	)		—		(58	)		—

Investments Classified by Contractual Maturity Date

The following table indicates the expected maturities of investment securities classified as available-for-sale presented at fair value, and held-to-maturity presented at amortized cost, at June 30, 2023 and the weighted average yield for each range of maturities (dollars in thousands):

	One year or less			After 1 through 5 years			After 5 through 10 years			After ten years			Total
Available-for-sale:
U.S. Treasury securities and obligations of U.S. government corporations and agencies	$	167,082		$	48,072		$	—		$	—		$	215,154
Obligations of state and political subdivisions		18,358			80,207			182,228			1,223			282,016
Mortgage-backed securities: GSE residential		2,429			7,456			24,730			559,133			593,748
Other securities		23,407			49,356			652			—			73,415
Total available-for-sale investments	$	211,276		$	185,091		$	207,610		$	560,356		$	1,164,333
Weighted average yield		1.64	%		2.51	%		2.04	%		1.70	%		1.87	%
Full tax-equivalent yield		1.67	%		2.51	%		2.06	%		1.72	%		1.89	%
Held to maturity:
Other investments	$	—		$	—		$	—		$	2,971		$	2,971
Total held-to-maturity	$	—		$	—		$	—		$	2,971		$	2,971
Weighted average yield		—	%		—	%		—	%		—	%		—	%
Full tax-equivalent yield		—	%		—	%		—	%		—	%		—	%

Fair Value of Investments with Sustained Gross Unrealized Losses

The following table presents the aging of gross unrealized losses and fair value by investment category as of June 30, 2023 and December 31, 2022 (in thousands):

	Less than 12 months					12 months or more					Total
	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
June 30, 2023
Available-for-sale:
U.S. Treasury securities and obligations of U.S. government corporations and agencies	$	1,553	$	(18	)	$	213,600	$	(31,540	)	$	215,153	$	(31,558	)
Obligations of states and political subdivisions		42,383		(591	)		230,437		(55,831	)		272,820		(56,422	)
Mortgage-backed securities: GSE residential		2,862		(95	)		590,760		(119,552	)		593,622		(119,647	)
Other securities		9,842		(901	)		57,824		(5,004	)		67,666		(5,905	)
Total	$	56,640	$	(1,605	)	$	1,092,621	$	(211,927	)	$	1,149,261	$	(213,532	)
December 31, 2022
Available-for-sale:
U.S. Treasury securities and obligations of U.S. government corporations and agencies	$	57,007	$	(3,493	)	$	163,520	$	(28,914	)	$	220,527	$	(32,407	)
Obligations of states and political subdivisions		220,102		(43,221	)		45,419		(16,624	)		265,521		(59,845	)
Mortgage-backed securities: GSE residential		165,966		(19,859	)		461,446		(96,900	)		627,412		(116,759	)
Other securities		64,676		(3,675	)		6,698		(844	)		71,374		(4,519	)
Total	$	507,751	$	(70,248	)	$	677,083	$	(143,282	)	$	1,184,834	$	(213,530	)