The following tables summarize the amortized cost, allowance for credit losses and fair value of the available-for-sale debt securities and the corresponding amounts of unrealized gains and losses recognized in accumulated other comprehensive income at September 30, 2022 and December 31, 2021:


	September 30, 2022
	Amortized cost		Gross unrealized gains		Gross unrealized losses		Allowance for credit losses for investments		Fair Value
Investment Securities
Available-for-sale debt securities
U.S. government agency securities	$	45,161	$	—	$	(5,330)	$	—	$	39,831
Mortgage-backed securities - residential	1,257,521		—		(199,758)		—		1,057,763
Mortgage-backed securities - commercial	19,453		—		(1,606)		—		17,847
Municipal securities	297,451		100		(45,408)		—		252,143
U.S. Treasury securities	113,198		—		(5,901)		—		107,297
Corporate securities	8,001		—		(711)		—		7,290
Total	$	1,740,785	$	100	$	(258,714)	$	—	$	1,482,171


	December 31, 2021
	Amortized cost		Gross unrealized gains		Gross unrealized losses		Allowance for credit losses for investments		Fair Value
Investment Securities
Available-for-sale debt securities
U.S. government agency securities	$	34,023	$	18	$	(171)	$	—	$	33,870
Mortgage-backed securities - residential	1,281,285		6,072		(17,985)		—		1,269,372
Mortgage-backed securities - commercial	15,024		272		(46)		—		15,250
Municipal securities	322,052		16,718		(160)		—		338,610
U.S. Treasury securities	14,914		—		(6)		—		14,908
Corporate securities	6,500		40		(25)		—		6,515
Total	$	1,673,798	$	23,120	$	(18,393)	$	—	$	1,678,525

The components of amortized cost for debt securities on the consolidated balance sheets excludes accrued interest receivable since the Company elected to present accrued interest receivable separately on the consolidated balance sheets. As of September 30, 2022 and December 31, 2021, total accrued interest receivable on debt securities was $5,535 and $5,051, respectively.

As of September 30, 2022 and December 31, 2021, the Company had $2,962 and $3,367, in marketable equity securities recorded at fair value, respectively.

Securities pledged at September 30, 2022 and December 31, 2021 had carrying amounts of $1,213,747 and $1,226,646, respectively, and were pledged to secure a Federal Reserve Bank line of credit, public deposits and repurchase agreements.

There were no holdings of securities of any one issuer, other than U.S. Government sponsored enterprises, in an amount greater than 10% of shareholders' equity during any period presented.

Investment securities transactions are recorded as of the trade date. At September 30, 2022 and December 31, 2021, there were no trade date receivables nor payables that related to sales or purchases settled after period end.

The amortized cost and fair value of debt securities by contractual maturity at September 30, 2022 and December 31, 2021 are shown below. Maturities may differ from contractual maturities in mortgage-backed securities because the mortgage underlying the security may be called or repaid without any penalties. Therefore, mortgage-backed securities are not included in the maturity categories in the following summary.


	September 30,				December 31,
	2022				2021
	Available-for-sale				Available-for-sale
	Amortized cost		Fair value		Amortized cost		Fair value
Due in one year or less	$	4,011	$	3,962	$	21,851	$	21,884
Due in one to five years	155,637		146,428		54,847		55,307
Due in five to ten years	62,157		56,759		45,714		46,975
Due in over ten years	242,006		199,412		255,077		269,737
	463,811		406,561		377,489		393,903
Mortgage-backed securities - residential	1,257,521		1,057,763		1,281,285		1,269,372
Mortgage-backed securities - commercial	19,453		17,847		15,024		15,250
Total debt securities	$	1,740,785	$	1,482,171	$	1,673,798	$	1,678,525


	Three Months Ended September 30,				Nine Months Ended September 30,
	2022		2021		2022		2021
Proceeds from sales	$	—	$	8,855	$	1,218	$	8,855
Proceeds from maturities, prepayments and calls	44,352		68,126		170,701		216,032
Gross realized gains	1		76		4		91
Gross realized losses	—		1		—		1

Additionally, changes in fair value and the sale of equity securities with readily determinable fair values resulted in a net loss of $141 and of $24 for the three months ended September 30, 2022 and 2021, respectively, and in a net loss of $405 and gain of $188 for the nine months ended September 30, 2022 and 2021, respectively.

The following tables show gross unrealized losses for which an allowance for credit losses has not been recorded at September 30, 2022 and December 31, 2021, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position:


	September 30, 2022
	Less than 12 months				12 months or more				Total
	Fair Value		Unrealized Loss		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
U.S. government agency securities	$	33,269	$	(4,207)	$	6,562	$	(1,123)	$	39,831	$	(5,330)
Mortgage-backed securities - residential	570,554		(84,615)		487,209		(115,143)		1,057,763		(199,758)
Mortgage-backed securities - commercial	16,709		(1,354)		1,138		(252)		17,847		(1,606)
Municipal securities	238,067		(42,452)		8,533		(2,956)		246,600		(45,408)
U.S. Treasury securities	107,297		(5,901)		—		—		107,297		(5,901)
Corporate securities	7,290		(711)		—		—		7,290		(711)
Total	$	973,186	$	(139,240)	$	503,442	$	(119,474)	$	1,476,628	$	(258,714)


	December 31, 2021
	Less than 12 months				12 months or more				Total
	Fair Value		Unrealized Loss		Fair Value		Unrealized Loss		Fair Value		Unrealized loss
U.S. government agency securities	$	18,360	$	(171)	$	—	$	—	$	18,360	$	(171)
Mortgage-backed securities - residential	$	871,368	$	(14,295)	$	102,799	$	(3,690)	$	974,167	$	(17,985)
Mortgage-backed securities - commercial	7,946		(46)		—		—		7,946		(46)
Municipal securities	11,414		(160)		—		—		11,414		(160)
U.S. Treasury securities	14,908		(6)		—		—		14,908		(6)
Corporate securities	4,119		(25)		—		—		4,119		(25)
Total	$	928,115	$	(14,703)	$	102,799	$	(3,690)	$	1,030,914	$	(18,393)

As of September 30, 2022 and December 31, 2021, the Company’s securities portfolio consisted of 504 and 511 securities, 487 and 80 of which were in an unrealized loss position, respectively.

During the three months ended September 30, 2022, the Company's available-for-sale debt securities portfolio unrealized value declined $91,104 to an unrealized loss position of $258,614 as of September 30, 2022 from an unrealized loss position of $167,510 as of June 30, 2022. During the nine months ended September 30, 2022, the Company's available-for-sale debt securities portfolio unrealized value declined $263,341 from an unrealized gain position of $4,727 as of December 31, 2021.

During the three months ended September 30, 2021, the Company's available-for-sale debt securities portfolio unrealized value decreased $7,947 to an unrealized gain position of $14,374 as of September 30, 2021 from an unrealized gain position of $22,321 as of June 30, 2021. During the nine months ended September 30, 2021, the Company's available-for-sale debt securities portfolio unrealized value declined $20,178 from an unrealized gain position of $34,552 as of December 31, 2020.