Investment Securities (Tables)

3 Months Ended

Mar. 31, 2022

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 March 31, 2022 and December 31, 2021 were as follows (in thousands):

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized (Losses)			Fair Value
March 31, 2022
Available-for-sale:
U.S. Treasury securities and obligations of U.S. government corporations and agencies	$	264,466	$	37	$	(16,527	)	$	247,976
Obligations of states and political subdivisions		386,489		2,713		(30,523	)		358,679
Mortgage-backed securities: GSE residential		820,448		245		(59,166	)		761,527
Other securities		99,812		274		(1,318	)		98,768
Total available-for-sale	$	1,571,215	$	3,269	$	(107,534	)	$	1,466,950
Held-to-maturity:
Other investments	$	2,998	$	—	$	—		$	2,998
Total held-to-maturity	$	2,998	$	—	$	—		$	2,998
December 31, 2021
Available-for-sale:
U.S. Treasury securities and obligations of U.S. government corporations and agencies	$	208,598	$	80	$	(4,863	)	$	203,815
Obligations of states and political subdivisions		383,991		12,123		(657	)		395,457
Mortgage-backed securities: GSE residential		799,456		4,292		(12,710	)		791,038
Other securities		30,546		671		(105	)		31,112
Total available-for-sale	$	1,422,591	$	17,166	$	(18,335	)	$	1,421,422
Held-to-maturity:
U.S. Treasury securities and obligations of U.S. government corporations and agencies	$	5,001	$	5	$	—		$	5,006
Other investments		2,029		—		—			2,029
U.S. Treasury securities and obligations of U.S. government corporations and agencies	$	7,030	$	5	$	—		$	7,035

Realized Gains and Losses From Sale of Securities

Realized gains and losses resulting from sales of securities were as follows during the three months ended March 31, 2022 and 2021 (in thousands):

	Three months March 31,
	2022		2021
Gross gains	$	—	$	4
Gross losses		—		—

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 March 31, 2022 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	$	155,050		$	82,575		$	10,351		$	—		$	247,976
Obligations of state and political subdivisions		20,894			94,654			241,873			1,258			358,679
Mortgage-backed securities: GSE residential		9,460			139,057			611,067			1,943			761,527
Other securities		22,747			74,575			1,446			—			98,768
Total available-for-sale investments	$	208,151		$	390,861		$	864,737		$	3,201		$	1,466,950
Weighted average yield		1.47	%		2.34	%		1.76	%		2.93	%		1.87	%
Full tax-equivalent yield		1.59	%		2.58	%		1.94	%		3.43	%		2.06	%
Held to maturity:
Other investments	$	—		$	—		$	—		$	2,998		$	2,998
Total held-to-maturity	$	—		$	—		$	—		$	2,998		$	2,998
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 March 31, 2022 and December 31, 2021 (in thousands):

	Less than 12 months					12 months or more					Total
	Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
March 31, 2022
Available-for-sale:
U.S. Treasury securities and obligations of U.S. government corporations and agencies	$	124,219	$	(5,410	)	$	116,577	$	(11,117	)	$	240,796	$	(16,527	)
Obligations of states and political subdivisions		231,248		(29,282	)		6,399		(1,241	)		237,647		(30,523	)
Mortgage-backed securities: GSE residential		546,117		(37,044	)		193,648		(22,122	)		739,765		(59,166	)
Other securities		80,465		(1,260	)		2,515		(58	)		82,980		(1,318	)
Total	$	982,049	$	(72,996	)	$	319,139	$	(34,538	)	$	1,301,188	$	(107,534	)
December 31, 2021
Available-for-sale:
U.S. Treasury securities and obligations of U.S. government corporations and agencies	$	48,316	$	(1,927	)	$	139,846	$	(2,936	)	$	188,162	$	(4,863	)
Obligations of states and political subdivisions		61,535		(657	)		—		—			61,535		(657	)
Mortgage-backed securities: GSE residential		562,699		(11,019	)		46,504		(1,691	)		609,203		(12,710	)
Other securities		7,976		(105	)		—		—			7,976		(105	)
Total	$	680,526	$	(13,708	)	$	186,350	$	(4,627	)	$	866,876	$	(18,335	)