Debt Securities Available for Sale (Tables)

9 Months Ended

Sep. 30, 2023

Investments, Debt and Equity Securities [Abstract]

Schedule of amortized cost, gross unrealized gains, gross unrealized losses and the fair value of securities available-for-sale

Debt securities available for sale at September 30, 2023 and December 31, 2022 are summarized as follows:

	September 30, 2023
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized (Losses)		Fair Value
	(In thousands)
U.S. government and agency obligations	$	96,364	$	27	$	(2,608)	$	93,783
Mortgage-backed securities and collateralized mortgage obligations	1,026,493		140		(182,373)		844,260
Municipal obligations	2,772		—		(108)		2,664
Corporate debt securities	92,531		9		(14,868)		77,672
	$	1,218,160	$	176	$	(199,957)	$	1,018,379

	December 31, 2022
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized (Losses)		Fair Value
			(In thousands)
U.S. government and agency obligations	$	67,771	$	—	$	(4,205)	$	63,566
Mortgage-backed securities and collateralized mortgage obligations	1,351,929		135		(170,337)		1,181,727
Municipal obligations	3,697		—		(122)		3,575
Corporate debt securities	92,544		6		(12,784)		79,766
	$	1,515,941	$	141	$	(187,448)	$	1,328,634

Schedule of securities by contractual maturity

The amortized cost and fair value of debt securities available for sale at September 30, 2023, by contractual final maturity, is shown below. Expected maturities may differ from contractual maturities due to prepayment or early call options exercised by the issuer.

	September 30, 2023
	Amortized Cost		Fair Value
	(In thousands)
One year or less	$	35,265	$	35,218
More than one year to five years	87,687		84,301
More than five years to ten years	68,715		54,600
	$	191,667	$	174,119
Mortgage-backed securities and collateralized mortgage obligations	1,026,493		844,260
	$	1,218,160	$	1,018,379

The amortized cost and fair value of debt securities held to maturity at September 30, 2023, by contractual final maturity, is shown below. Expected maturities may differ from contractual maturities due to prepayment or early call options exercised by the issuer.

	September 30, 2023
	Amortized Cost		Fair Value
	(In thousands)
More than one year to five years	$	29,875	$	26,783
More than five years to ten years	9,996		8,022
More than ten years	10,000		7,085
	49,871		41,890
Mortgage-backed securities and collateralized mortgage obligations	362,074		310,037
	$	411,945	$	351,927

Debt securities, available-for-sale, unrealized loss position, fair value

The following tables summarize the fair value and gross unrealized losses of those securities that reported an unrealized loss at September 30, 2023 and December 31, 2022 and if the unrealized loss position was continuous for the twelve months prior to those respective dates:

	September 30, 2023
	Less Than 12 Months				12 Months or Longer				Total
	Fair Value		Gross Unrealized (Losses)		Fair Value		Gross Unrealized (Losses)		Fair Value		Gross Unrealized (Losses)
	(In thousands)
U.S. government and agency obligations	$	73,213	$	(230)	$	18,844	$	(2,378)	$	92,057	$	(2,608)
Mortgage-backed securities and collateralized mortgage obligations	11,183		(715)		821,064		(181,658)		832,247		(182,373)
Municipal obligations	—		—		2,664		(108)		2,664		(108)
Corporate debt securities	—		—		70,663		(14,868)		70,663		(14,868)
	$	84,396	$	(945)	$	913,235	$	(199,012)	$	997,631	$	(199,957)

	December 31, 2022
	Less Than 12 Months				12 Months or Longer				Total
	Fair Value		Gross Unrealized (Losses)		Fair Value		Gross Unrealized (Losses)		Fair Value		Gross Unrealized (Losses)
	(In thousands)
U.S. government and agency obligations	$	47,956	$	(2,359)	$	15,610	$	(1,846)	$	63,566	$	(4,205)
Mortgage-backed securities and collateralized mortgage obligations	424,328		(29,013)		741,515		(141,324)		1,165,843		(170,337)
Municipal obligations	3,574		(122)		—		—		3,574		(122)
Corporate debt securities	46,751		(5,792)		31,008		(6,992)		77,759		(12,784)
	$	522,609	$	(37,286)	$	788,133	$	(150,162)	$	1,310,742	$	(187,448)

Debt Securities, Available-for-sale, Allowance for Credit Loss

The following table presents the activity in the allowance for credit losses on debt securities available for sale for the three and nine months ended September 30, 2023 and 2022:

	For the Three Months Ended September 30,				For the Nine Months Ended September 30,
	2023		2022		2023		2022
	(In thousands)
Allowance for Credit Losses:
Beginning balance	$	—	$	—	$	—	$	—
Impact of adopting ASU 2016-13 (CECL) effective January 1, 2022	—		—		—		490
Provision for credit losses	—		—		—		(490)
Ending balance	$	—	$	—	$	—	$	—