Debt Securities Available for Sale (Tables)

12 Months Ended

Dec. 31, 2021

Investments, Debt and Equity Securities [Abstract]

Debt securities, available-for-sale

Debt securities available for sale at December 31, 2021 and 2020 are summarized as follows:

	December 31, 2021
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized (Losses)		Fair Value
			(In thousands)
U.S. government and agency obligations	$	34,711	$	404	$	(236)	$	34,879
Mortgage-backed securities and collateralized mortgage obligations	1,553,491		14,141		(13,273)		1,554,359
Municipal obligations	4,159		20		—		4,179
Corporate debt securities	109,018		2,378		(966)		110,430
	$	1,701,379	$	16,943	$	(14,475)	$	1,703,847

	December 31, 2020
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized (Losses)		Fair Value
			(In thousands)
U.S. government and agency obligations	$	24,425	$	1,124	$	—	$	25,549
Mortgage-backed securities and collateralized mortgage obligations	1,163,613		37,343		(562)		1,200,394
Municipal obligations	16,845		17		—		16,862
Corporate debt securities	67,628		2,264		(415)		69,477
Trust preferred securities	5,000		—		(330)		4,670
	$	1,277,511	$	40,748	$	(1,307)	$	1,316,952

Investments classified by contractual maturity date

The amortized cost and fair value of debt securities available for sale at December 31, 2021, 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.

	December 31, 2021
	Amortized Cost		Fair Value
	(In thousands)
One year or less	$	5,912	$	5,998
More than one year to five years	80,419		82,493
More than five years to ten years	61,557		60,997
	$	147,888	$	149,488
Mortgage-backed securities and collateralized mortgage obligations	1,553,491		1,554,359
	$	1,701,379	$	1,703,847

Expected maturities may differ from contractual maturities due to prepayment or early call options exercised by the issuer.

	December 31, 2021
	Amortized Cost		Fair Value
	(In thousands)
More than one year to five years	$	14,875	$	14,754
More than five years to ten years	19,995		19,539
More than ten years	10,000		9,818
	44,870		44,111
Mortgage-backed securities and collateralized mortgage obligations	384,864		390,678
	$	429,734	$	434,789

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 December 31, 2021 and 2020 and if the unrealized loss position was continuous for the twelve months prior to those respective dates:

	December 31, 2021
	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	$	14,488	$	(236)	$	—	$	—	$	14,488	$	(236)
Mortgage-backed securities and collateralized mortgage obligations	820,746		(11,892)		62,407		(1,381)		883,153		(13,273)
Corporate debt securities	29,221		(671)		4,705		(295)		33,926		(966)
	$	864,455	$	(12,799)	$	67,112	$	(1,676)	$	931,567	$	(14,475)

	December 31, 2020
	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)
Mortgage-backed securities and collateralized mortgage obligations	$	117,978	$	(481)	$	24,018	$	(81)	$	141,996	$	(562)
Corporate debt securities	9,845		(155)		5,740		(260)		15,585		(415)
Trust preferred securities	—		—		4,670		(330)		4,670		(330)
	$	127,823	$	(636)	$	34,428	$	(671)	$	162,251	$	(1,307)