Securities (Tables)

9 Months Ended

Sep. 30, 2021

Investments, Debt and Equity Securities [Abstract]

Summary of Amortized Cost and Fair Value of Securities Available for Sale

The amortized cost, gross unrealized gains and losses and fair value of securities available-for-sale and held-to-maturity at September 30, 2021 and December 31, 2020 are summarized as follows:

	September 30, 2021
(In thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Debt securities available-for-sale
U.S. Treasury securities and obligations of U.S. government agencies	$	6,785	$	371	$	(2)	$	7,154
Mortgage-backed securities and collateralized mortgage obligations of U.S. government-sponsored entities	1,147,743		12,378		(9,450)		1,150,671
Private mortgage-backed securities and collateralized mortgage obligations	75,754		1,710		(236)		77,228
Collateralized loan obligations	277,262		149		(105)		277,306
Obligations of state and political subdivisions	32,016		1,837		(57)		33,796
Totals	$	1,539,560	$	16,445	$	(9,850)	$	1,546,155
Debt securities held-to-maturity
Mortgage-backed securities and collateralized mortgage obligations of U.S. government-sponsored entities	$	526,502	$	4,702	$	(12,740)	$	518,464
Totals	$	526,502	$	4,702	$	(12,740)	$	518,464

	December 31, 2020
(In thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Debt securities available-for-sale
U.S. Treasury securities and obligations of U.S. government agencies	$	8,250	$	528	$	(1)	$	8,777
Mortgage-backed securities and collateralized mortgage obligations of U.S. government-sponsored entities	1,038,437		23,457		(1,240)		1,060,654
Private mortgage-backed securities and collateralized mortgage obligations	89,284		2,131		(210)		91,205
Collateralized loan obligations	202,563		279		(647)		202,195
Obligations of state and political subdivisions	33,005		2,321		—		35,326
Totals	$	1,371,539	$	28,716	$	(2,098)	$	1,398,157
Debt securities held-to-maturity
Mortgage-backed securities of U.S. government-sponsored entities	$	184,484	$	7,818	$	(123)	$	192,179
Totals	$	184,484	$	7,818	$	(123)	$	192,179

Summary of Amortized Cost and Fair Value of Held-to-Maturity Securities

The amortized cost, gross unrealized gains and losses and fair value of securities available-for-sale and held-to-maturity at September 30, 2021 and December 31, 2020 are summarized as follows:

	September 30, 2021
(In thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Debt securities available-for-sale
U.S. Treasury securities and obligations of U.S. government agencies	$	6,785	$	371	$	(2)	$	7,154
Mortgage-backed securities and collateralized mortgage obligations of U.S. government-sponsored entities	1,147,743		12,378		(9,450)		1,150,671
Private mortgage-backed securities and collateralized mortgage obligations	75,754		1,710		(236)		77,228
Collateralized loan obligations	277,262		149		(105)		277,306
Obligations of state and political subdivisions	32,016		1,837		(57)		33,796
Totals	$	1,539,560	$	16,445	$	(9,850)	$	1,546,155
Debt securities held-to-maturity
Mortgage-backed securities and collateralized mortgage obligations of U.S. government-sponsored entities	$	526,502	$	4,702	$	(12,740)	$	518,464
Totals	$	526,502	$	4,702	$	(12,740)	$	518,464

	December 31, 2020
(In thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Debt securities available-for-sale
U.S. Treasury securities and obligations of U.S. government agencies	$	8,250	$	528	$	(1)	$	8,777
Mortgage-backed securities and collateralized mortgage obligations of U.S. government-sponsored entities	1,038,437		23,457		(1,240)		1,060,654
Private mortgage-backed securities and collateralized mortgage obligations	89,284		2,131		(210)		91,205
Collateralized loan obligations	202,563		279		(647)		202,195
Obligations of state and political subdivisions	33,005		2,321		—		35,326
Totals	$	1,371,539	$	28,716	$	(2,098)	$	1,398,157
Debt securities held-to-maturity
Mortgage-backed securities of U.S. government-sponsored entities	$	184,484	$	7,818	$	(123)	$	192,179
Totals	$	184,484	$	7,818	$	(123)	$	192,179

Summary of Investments Classified by Contractual Maturity

Securities not due at a single maturity date are shown separately.

	September 30, 2021
	Held-to-Maturity				Available-for-Sale
(In thousands)	Amortized Cost		Fair Value		Amortized Cost		Fair Value
Due in less than one year	$	—	$	—	$	1,418	$	1,442
Due after one year through five years	—		—		13,892		14,828
Due after five years through ten years	—		—		8,376		8,764
Due after ten years	—		—		15,115		15,916
	—		—		38,801		40,950
Mortgage-backed securities and collateralized mortgage obligations of U.S. government-sponsored entities	526,502		518,464		1,147,743		1,150,671
Private mortgage-backed securities and collateralized mortgage obligations	—		—		75,754		77,228
Collateralized loan obligations	—		—		277,262		277,306
Totals	$	526,502	$	518,464	$	1,539,560	$	1,546,155

Schedule of Debt Securities in Unrealized Loss Position

The tables below indicate the fair value of available-for-sale debt securities with unrealized losses for which no allowance for credit losses has been recorded.

	September 30, 2021
	Less Than 12 Months				12 Months or Longer				Total
(In thousands)	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
U.S. Treasury securities and obligations of U.S. government agencies	$	—	$	—	$	248	$	(2)	$	248	$	(2)
Mortgage-backed securities and collateralized mortgage obligations of U.S. government-sponsored entities	660,028		(8,696)		15,350		(754)		675,378		(9,450)
Private mortgage-backed securities and collateralized mortgage obligations	13,018		(206)		2,710		(30)		15,728		(236)
Collateralized loan obligations	64,232		(58)		9,459		(47)		73,691		(105)
Obligations of state and political subdivisions	5,443		(57)		—		—		5,443		(57)
Totals	$	742,721	$	(9,017)	$	27,767	$	(833)	$	770,488	$	(9,850)

	December 31, 2020
	Less Than 12 Months				12 Months or Longer				Total
(In thousands)	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
U.S. Treasury securities and obligations of U.S. government agencies	$	—	$	—	$	256	$	(1)	$	256	$	(1)
Mortgage-backed securities and collateralized mortgage obligations of U.S. government-sponsored entities	203,405		(1,218)		569		(22)		203,974		(1,240)
Private mortgage-backed securities and collateralized mortgage obligations	23,997		(210)		—		—		23,997		(210)
Collateralized loan obligations	104,697		(102)		72,513		(545)		177,210		(647)
Totals	$	332,099	$	(1,530)	$	73,338	$	(568)	$	405,437	$	(2,098)