Investment Securities (Tables)

9 Months Ended

Sep. 30, 2021

Investments, Debt and Equity Securities [Abstract]

Schedule of available-for-sale securities reconciliation

The following table presents amortized cost, gross unrealized gains and losses, and fair values of securities available-for-sale as of the dates indicated:

	September 30, 2021								December 31, 2020
			Gross		Gross						Gross		Gross
	Amortized		Unrealized		Unrealized		Fair		Amortized		Unrealized		Unrealized		Fair
Security Type	Cost		Gains		Losses		Value		Cost		Gains		Losses		Value
	(In thousands)
Agency residential MBS	$	2,185,544	$	11,236	$	(15,787)	$	2,180,993	$	329,488	$	12,483	$	(897)	$	341,074
Municipal securities	1,929,753		67,167		(6,991)		1,989,929		1,438,004		93,631		(18)		1,531,617
Agency commercial MBS	1,269,984		49,063		(5,023)		1,314,024		1,207,676		74,238		(37)		1,281,877
Agency residential CMOs	1,062,836		29,440		(3,739)		1,088,537		1,172,166		47,994		(280)		1,219,880
U.S. Treasury securities	973,307		2,060		(4,099)		971,268		4,989		313		—		5,302
Corporate debt securities	505,800		11,976		(1,161)		516,615		308,803		3,490		(404)		311,889
Private label commercial MBS	389,030		716		(1,428)		388,318		81,878		1,089		(10)		82,957
Collateralized loan obligations	359,057		163		(673)		358,547		136,777		23		(924)		135,876
Private label residential CMOs	301,743		3,508		(1,570)		303,681		110,891		6,076		(21)		116,946
Asset-backed securities	132,421		855		(279)		132,997		166,861		445		(760)		166,546
SBA securities	30,849		1,185		(17)		32,017		39,437		2,217		(27)		41,627
Total	$	9,140,324	$	177,369	$	(40,767)	$	9,276,926	$	4,996,970	$	241,999	$	(3,378)	$	5,235,591

Schedule of realized gains and losses on securities available-for-sale

The following table presents the amortized cost of securities sold with related gross realized gains, gross realized losses, and net realized gains for the years indicated:

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
Sales of Securities Available-for-Sale	2021		2020		2021		2020
	(In thousands)
Amortized cost of securities sold	$	76,184	$	17,000	$	120,735	$	154,100
Gross realized gains	$	517	$	5,270	$	618	$	13,199
Gross realized losses	(2)		—		(2)		(32)
Net realized gains	$	515	$	5,270	$	616	$	13,167

Unrealized losses on investment securities

The following tables present the gross unrealized losses and fair values of securities available-for-sale that were in unrealized loss positions as of the dates indicated:

	September 30, 2021
	Less Than 12 Months				12 Months or More				Total
			Gross				Gross				Gross
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
Security Type	Value		Losses		Value		Losses		Value		Losses
	(In thousands)
Agency residential MBS	$	1,697,399	$	(15,779)	$	680	$	(8)	$	1,698,079	$	(15,787)
Municipal securities	583,499		(6,860)		2,559		(131)		586,058		(6,991)
Agency commercial MBS	282,753		(5,023)		—		—		282,753		(5,023)
Agency residential CMOs	189,684		(3,700)		11,283		(39)		200,967		(3,739)
U.S. Treasury securities	632,950		(4,099)		—		—		632,950		(4,099)
Corporate debt securities	127,786		(1,161)		—		—		127,786		(1,161)
Private label commercial MBS	266,238		(1,428)		—		—		266,238		(1,428)
Collateralized loan obligations	202,528		(600)		43,930		(73)		246,458		(673)
Private label residential CMOs	234,541		(1,555)		319		(15)		234,860		(1,570)
Asset-backed securities	25,044		(49)		16,126		(230)		41,170		(279)
SBA securities	—		—		1,897		(17)		1,897		(17)
Total	$	4,242,422	$	(40,254)	$	76,794	$	(513)	$	4,319,216	$	(40,767)

	December 31, 2020
	Less Than 12 Months				12 Months or More				Total
			Gross				Gross				Gross
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
Security Type	Value		Losses		Value		Losses		Value		Losses
	(In thousands)
Agency residential MBS	$	90,722	$	(897)	$	—	$	—	$	90,722	$	(897)
Municipal securities	5,919		(18)		—		—		5,919		(18)
Agency commercial MBS	58,408		(37)		—		—		58,408		(37)
Agency residential CMOs	97,863		(280)		—		—		97,863		(280)
Corporate debt securities	87,596		(404)		—		—		87,596		(404)
Private label commercial MBS	3,058		(10)		—		—		3,058		(10)
Collateralized loan obligations	96,442		(729)		28,972		(195)		125,414		(924)
Private label residential CMOs	788		(19)		74		(2)		862		(21)
Asset-backed securities	14,636		(53)		61,031		(707)		75,667		(760)
SBA securities	2,127		(27)		—		—		2,127		(27)
Total	$	457,559	$	(2,474)	$	90,077	$	(904)	$	547,636	$	(3,378)

Investments classified by contractual maturity date

The following table presents the contractual maturities of our securities available-for-sale portfolio based on amortized cost and carrying value as of the date indicated:

	September 30, 2021
	Amortized		Fair
Maturities	Cost		Value
	(In thousands)
Due in one year or less	$	40,903	$	41,218
Due after one year through five years	578,943		606,629
Due after five years through ten years	2,991,339		3,029,128
Due after ten years	5,529,139		5,599,951
Total securities available-for-sale	$	9,140,324	$	9,276,926

Investment income

The following table presents the composition of our interest income on investment securities for the periods indicated:

	Three Months Ended				Nine Months Ended
	September 30,				September 30,
	2021		2020		2021		2020
	(In thousands)
Taxable interest	$	31,980	$	17,835	$	79,156	$	59,457
Non-taxable interest	8,542		6,272		25,113		17,113
Dividend income	258		336		730		1,357
Total interest income on investment securities	$	40,780	$	24,443	$	104,999	$	77,927