Debt Securities Available-for-Sale (Tables)

3 Months Ended

Mar. 31, 2022

Investments, Debt and Equity Securities [Abstract]

Comparative Summary of Mortgage-Backed Securities and Other Securities Available-for-Sale

The following is a comparative summary of mortgage-backed securities and other debt securities available-for-sale at March 31, 2022, and December 31, 2021 (in thousands):

	March 31, 2022
			Gross		Gross		Estimated
	Amortized		unrealized		unrealized		fair
	cost		gains		losses		value
U.S. Government agency securities	$	76,572	$	—	$	(952)	$	75,620
Mortgage-backed securities:
Pass-through certificates:
Government sponsored enterprises ("GSEs")	584,788		1,339		(21,737)		564,390
Real estate mortgage investment conduits ("REMICs"):
GSE	317,373		100		(6,370)		311,103
	902,161		1,439		(28,107)		875,493
Other debt securities:
Municipal bonds	52		—		—		52
Corporate bonds	207,929		75		(4,892)		203,112
	207,981		75		(4,892)		203,164
Total debt securities available-for-sale	$	1,186,714	$	1,514	$	(33,951)	$	1,154,277

	December 31, 2021
			Gross		Gross		Estimated
	Amortized		unrealized		unrealized		fair
	cost		gains		losses		value
U.S. Government agency securities	$	2,344	$	—	$	(54)	$	2,290
Mortgage-backed securities:
Pass-through certificates:
GSE	579,035		5,233		(2,862)		581,406
REMICs:
GSE	390,755		2,398		(1,443)		391,710
	969,790		7,631		(4,305)		973,116
Other debt securities:
Municipal bonds	71		1		—		72
Corporate bonds	233,311		192		(744)		232,759
	233,382		193		(744)		232,831
Total debt securities available-for-sale	$	1,205,516	$	7,824	$	(5,103)	$	1,208,237

Summary of Expected Maturity Distribution of Debt Securities Available-for-Sale, Other Than Mortgage-Backed Securities

The following is a summary of the expected maturity distribution of debt securities available-for-sale, other than mortgage-backed securities, at March 31, 2022 (in thousands):

Available-for-sale	Amortized cost		Estimated fair value
Due in one year or less	$	118,900	$	117,947
Due after one year through five years	164,080		159,377
Due after five years through ten years	1,573		1,460
	$	284,553	$	278,784

Gross Unrealized Losses on Mortgage-Backed Securities

Gross unrealized losses on mortgage-backed securities and other debt securities available-for-sale, and the estimated fair value of the related securities, aggregated by security category and length of time that individual securities have been in a continuous unrealized loss position, at March 31, 2022 and December 31, 2021, were as follows (in thousands):

	March 31, 2022
	Less than 12 months				12 months or more				Total
	Unrealized		Estimated		Unrealized		Estimated		Unrealized		Estimated
	losses		fair value		losses		fair value		losses		fair value
U.S. Government agency securities	$	(839)	$	74,161	$	(113)	$	1,459	$	(952)	$	75,620
Mortgage-backed securities:
Pass-through certificates:
GSE	(21,102)		456,299		(635)		12,716		(21,737)		469,015
REMICs:
GSE	(3,531)		211,385		(2,839)		66,845		(6,370)		278,230
Other debt securities:
Corporate bonds	(3,738)		158,396		(1,154)		13,856		(4,892)		172,252
Total	$	(29,210)	$	900,241	$	(4,741)	$	94,876	$	(33,951)	$	995,117

	December 31, 2021
	Less than 12 months				12 months or more				Total
	Unrealized		Estimated		Unrealized		Estimated		Unrealized		Estimated
	losses		fair value		losses		fair value		losses		fair value
U.S. Government agency securities	$	—	$	—	$	(54)	$	2,290	$	(54)	$	2,290
Mortgage-backed securities:
Pass-through certificates:
GSE	(2,543)		417,291		(318)		14,625		(2,861)		431,916
REMICs:
GSE	(1,350)		125,725		(94)		4,413		(1,444)		130,138
Other debt securities:
Corporate bonds	(744)		146,853		—		—		(744)		146,853
Total	$	(4,637)	$	689,869	$	(466)	$	21,328	$	(5,103)	$	711,197

Gross unrealized losses on mortgage-backed securities held-to-maturity, and the estimated fair value of the related securities, aggregated by security category and length of time that individual securities have been in a continuous unrealized loss position at March 31, 2022 were as follows (in thousands):

	March 31, 2022
	Less than 12 months				12 months or more				Total
	Unrealized		Estimated		Unrealized		Estimated		Unrealized		Estimated
	losses		fair value		losses		fair value		losses		fair value
Mortgage-backed securities:
Pass-through certificates:
GSE	$	(75)	$	3,814	$	—	$	—	$	(75)	$	3,814
Total	$	(75)	$	3,814	$	—	$	—	$	(75)	$	3,814