Investment securities

3 Months Ended

Mar. 31, 2021

Investments, Debt and Equity Securities [Abstract]

Investment securities

Investment securities:

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 March 31, 2021 and December 31, 2020:  

	March 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
Mortgage-backed securities - residential	$	834,335	$	10,971	$	(6,598)	$	—	$	838,708
Mortgage-backed securities - commercial	19,888		757		(10)		—		20,635
Municipal securities	334,730		14,515		(469)		—		348,776
U.S. Treasury securities	14,480		96		—		—		14,576
Corporate securities	2,500		—		(17)		—		2,483
Total	$	1,205,933	$	26,339	$	(7,094)	$	—	$	1,225,178

	December 31, 2020
	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	$	2,000	$	3	$	—	$	—	$	2,003
Mortgage-backed securities - residential	760,099		14,040		(803)		—		773,336
Mortgage-backed securities - commercial	20,226		1,362		—		—		21,588
Municipal securities	336,543		19,806		(20)		—		356,329
U.S. Treasury securities	16,480		148		—		—		16,628
Corporate securities	2,500		17		(1)		—		2,516
Total	$	1,137,848	$	35,376	$	(824)	$	—	$	1,172,400

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 March 31, 2021 and December 31, 2020, total accrued interest receivable on debt securities was $4,380 and $4,540, respectively.

As of March 31, 2021 and December 31, 2020, the Company had $4,667 and $4,591, respectively, in marketable equity securities recorded at fair value, respectively.

Securities pledged at March 31, 2021 and December 31, 2020 had carrying amounts of $869,390 and $804,821, 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 the U.S. Government and its agencies, in an amount greater than 10% of shareholders' equity during any period presented.

At March 31, 2021 and December 31, 2020, there were no trade date payables that related to purchases settled after period end.

The amortized cost and fair value of debt securities by contractual maturity at March 31, 2021 and December 31, 2020 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 maturity summary.

	March 31,				December 31,
	2021				2020
	Available-for-sale				Available-for-sale
	Amortized cost		Fair value		Amortized cost		Fair value
Due in one year or less	$	36,486	$	36,660	$	35,486	$	35,662
Due in one to five years	14,008		21,113		24,278		24,684
Due in five to ten years	36,838		38,377		40,038		41,332
Due in over ten years	264,378		269,685		257,721		275,798
	351,710		365,835		357,523		377,476
Mortgage-backed securities - residential	834,335		838,708		760,099		773,336
Mortgage-backed securities - commercial	19,888		20,635		20,226		21,588
Total debt securities	$	1,205,933	$	1,225,178	$	1,137,848	$	1,172,400

Sales and other dispositions of available-for-sale securities were as follows:

	Three Months Ended March 31,
	2021		2020
Proceeds from sales	$	—	$	—
Proceeds from maturities, prepayments and calls	61,040		27,657
Gross realized gains	7		—
Gross realized losses	—		—

Additionally, net unrealized gains on equity securities of $76 and $63 were recognized in the three months ended March 31, 2021 and 2020, respectively.

The following tables show gross unrealized losses for which an allowance for credit losses has not been recorded at March 31, 2021 and December 31, 2020, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position:

	March 31, 2021
	Less than 12 months				12 months or more				Total
	Fair Value		Unrealized Loss		Fair Value		Unrealized Loss		Fair Value		Unrealized Loss
Mortgage-backed securities - residential	$	402,455	$	(6,598)	$	—	$	—	$	402,455	$	(6,598)
Mortgage-backed securities - commercial	20,636		(10)		—		—		20,636		(10)
Municipal securities	60,771		(469)		—		—		60,771		(469)
Corporate securities	1,983		(17)		—		—		1,983		(17)
Total	$	485,845	$	(7,094)	$	—	$	—	$	485,845	$	(7,094)

	December 31, 2020
	Less than 12 months				12 months or more				Total
	Fair Value		Unrealized Loss		Fair Value		Unrealized Loss		Fair Value		Unrealized loss
Mortgage-backed securities - residential	$	182,012	$	(803)	$	—	$	—	$	182,012	$	(803)
Municipal securities	3,184		(20)		—		—		3,184		(20)
Corporate Securities	499		(1)						499		(1)
Total	$	185,695	$	(824)	$	—	$	—	$	185,695	$	(824)

As of March 31, 2021 and December 31, 2020, the Company’s securities portfolio consisted of 511 and 514 securities, 42 and 16 of which were in an unrealized loss position, respectively.

As of March 31, 2021 and 2020, the Company evaluated available-for-sale debt securities with unrealized losses for expected credit loss and recorded no allowance for credit loss as the majority of the investment portfolio was either government guaranteed or an issuance of a government sponsored entity, was highly rated by major credit rating agencies and have a long history of zero losses. As such, no provision for credit losses was recorded during the three months ended March 31, 2021 and 2020.