Debt Securities Available for Sale (Tables)

6 Months Ended

Jun. 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 June 30, 2023 and December 31, 2022 are summarized as follows:

	June 30, 2023
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized (Losses)		Fair Value
	(In thousands)
U.S. government and agency obligations	$	23,445	$	—	$	(2,519)	$	20,926
Mortgage-backed securities and collateralized mortgage obligations	1,054,116		42		(157,339)		896,819
Municipal obligations	3,693		—		(107)		3,586
Corporate debt securities	92,535		5		(16,412)		76,128
	$	1,173,789	$	47	$	(176,377)	$	997,459

	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 June 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.

	June 30, 2023
	Amortized Cost		Fair Value
	(In thousands)
One year or less	$	920	$	917
More than one year to five years	54,891		50,578
More than five years to ten years	63,862		49,145
	$	119,673	$	100,640
Mortgage-backed securities and collateralized mortgage obligations	1,054,116		896,819
	$	1,173,789	$	997,459

The amortized cost and fair value of debt securities held to maturity at June 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.

	June 30, 2023
	Amortized Cost		Fair Value
	(In thousands)
More than one year to five years	$	19,875	$	18,385
More than five years to ten years	19,996		16,827
More than ten years	10,000		7,623
	49,871		42,835
Mortgage-backed securities and collateralized mortgage obligations	365,462		321,276
	$	415,333	$	364,111

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 June 30, 2023 and December 31, 2022 and if the unrealized loss position was continuous for the twelve months prior to those respective dates:

	June 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	$	1,299	$	(163)	$	19,627	$	(2,356)	$	20,926	$	(2,519)
Mortgage-backed securities and collateralized mortgage obligations	22,303		(1,388)		869,764		(155,951)		892,067		(157,339)
Municipal obligations	455		(7)		3,131		(100)		3,586		(107)
Corporate debt securities	1,745		(255)		72,378		(16,157)		74,123		(16,412)
	$	25,802	$	(1,813)	$	964,900	$	(174,564)	$	990,702	$	(176,377)

6.    Debt Securities Available for Sale (continued)

	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 six months ended June 30, 2023 and 2022:

	For the Three Months Ended June 30,				For the Six Months Ended June 30,
	2023		2022		2023		2022
	(In thousands)
Allowance for Credit Losses:
Beginning balance	$	—	$	1,144	$	—	$	—
Impact of adopting ASU 2016-13 (CECL) effective January 1, 2022	—		—		—		490
Provision for credit losses	—		(1,144)		—		(490)
Ending balance	$	—	$	—	$	—	$	—