Investment Securities (Tables)

6 Months Ended

Jun. 30, 2021

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, 2021 and December 31, 2020 were as follows (in thousands):

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized (Losses)			Fair Value
June 30, 2021
Available-for-sale:
U.S. Treasury securities and obligations of U.S.    government corporations and agencies	$	194,722	$	310	$	(2,853	)	$	192,179
Obligations of states and political subdivisions		294,255		11,751		(380	)		305,626
Mortgage-backed securities: GSE residential		685,736		7,119		(4,285	)		688,570
Other securities		35,118		733		(28	)		35,823
Total available-for-sale	$	1,209,831	$	19,913	$	(7,546	)	$	1,222,198
Held-to-maturity:
U.S. Treasury securities and obligations of    U.S. government corporations and agencies	$	5,008	$	56	$	—		$	5,064
Other securities		2,041		—		—			2,041
Total held-to-maturity	$	7,049	$	56	$	—		$	7,105
December 31, 2020
Available-for-sale:
U.S. Treasury securities and obligations of U.S.    government corporations and agencies	$	127,067	$	790	$	(788	)	$	127,069
Obligations of states and political subdivisions		237,886		11,995		(37	)		249,844
Mortgage-backed securities: GSE residential		479,470		12,038		(160	)		491,348
Other securities		10,740		252		(13	)		10,979
Total available-for-sale	$	855,163	$	25,075	$	(998	)	$	879,240
Held-to-maturity:
U.S. Treasury securities and obligations of U.S.    government corporations and agencies	$	5,016	$	103	$	—		$	5,119

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, 2021 and 2020 (in thousands):

	Three months June 30,				Six months June 30,
	2021		2020		2021		2020
Gross gains	$	73	$	287	$	77	$	818
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 June 30, 2021 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	$	116,012		$	64,894		$	11,273		$	—		$	192,179
Obligations of state and political subdivisions		25,869			81,102			190,196			8,459			305,626
Mortgage-backed securities: GSE residential		18,751			326,494			343,325			—			688,570
Other securities		10,100			24,217			1,506			—			35,823
Total available-for-sale investments	$	170,732		$	496,707		$	546,300		$	8,459		$	1,222,198
Weighted average yield		1.64	%		2.14	%		1.65	%		2.12	%		1.85	%
Full tax-equivalent yield		1.80	%		2.31	%		1.90	%		2.72	%		2.06	%
Held to maturity:
U.S. Treasury securities and obligations of    U.S. government corporations and agencies	$	5,008		$	—		$	—		$	—		$	5,008
Other securities		—									2,041			2,041
Total held-to-maturity	$	5,008		$	—		$	—		$	2,041		$	7,049
Weighted average yield		2.06	%		—	%		—	%		—	%		2.06	%
Full tax-equivalent yield		2.06	%		—	%		—	%		—	%		2.06	%

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, 2021 and December 31, 2020 (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, 2021
Available-for-sale:
U.S. Treasury securities and obligations of    U.S. government corporations and agencies	$	165,101	$	(2,853	)	$	—	$	—		$	165,101	$	(2,853	)
Obligations of states and political subdivisions		42,220		(380	)		—		—			42,220		(380	)
Mortgage-backed securities: GSE residential		219,104		(3,441	)		121,550		(844	)		340,654		(4,285	)
Other securities		8,582		(28	)		—		—			8,582		(28	)
Total	$	435,007	$	(6,702	)	$	121,550	$	(844	)	$	556,557	$	(7,546	)
December 31, 2020
Available-for-sale:
U.S. Treasury securities and obligations of    U.S. government corporations and agencies	$	59,211	$	(788	)	$	—	$	—		$	59,211	$	(788	)
Obligations of states and political subdivisions		5,380		(37	)		—		—			5,380		(37	)
Mortgage-backed securities: GSE residential		57,609		(160	)		2,377		—			59,986		(160	)
Other securities		3,977		(13	)		—		—			3,977		(13	)
Total	$	126,177	$	(998	)	$	2,377	$	—		$	128,554	$	(998	)