Debt Securities Available-for-Sale (Tables)

3 Months Ended

Mar. 31, 2020

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 and other debt securities available-for-sale at March 31, 2020, and December 31, 2019 (in thousands):

	March 31, 2020
			Gross		Gross		Estimated
	Amortized		unrealized		unrealized		fair
	cost		gains		losses		value
Mortgage-backed securities:
Pass-through certificates:
Government sponsored enterprises (GSE)	$	300,610	$	10,340	$	81	$	310,869
Real estate mortgage investment conduits (REMICs):
GSE	618,156		6,336		912		623,580
Non-GSE	51		—		2		49
	918,817		16,676		995		934,498
Other debt securities:
Municipal bonds	278		1		—		279
Corporate bonds	127,643		419		1,396		126,666
	127,921		420		1,396		126,945
Total debt securities available-for-sale	$	1,046,738	$	17,096	$	2,391	$	1,061,443

	December 31, 2019
			Gross		Gross		Estimated
	Amortized		unrealized		unrealized		fair
	cost		gains		losses		value
Mortgage-backed securities:
Pass-through certificates:
GSE	$	324,080	$	6,081	$	754	$	329,407
REMICs:
GSE	643,816		2,076		2,225		643,667
Non-GSE	53		—		—		53
	967,949		8,157		2,979		973,127
Other debt securities:
Municipal bonds	296		3		—		299
Corporate bonds	163,725		1,214		13		164,926
	164,021		1,217		13		165,225
Total debt securities available-for-sale	$	1,131,970	$	9,374	$	2,992	$	1,138,352

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, 2020 (in thousands):

Available-for-sale	Amortized cost		Estimated fair value
Due in one year or less	$	77,203	$	76,941
Due after one year through five years	50,718		50,004
	$	127,921	$	126,945

Gross Unrealized Losses on Mortgage-Backed Securities

Gross unrealized losses on mortgage-backed 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, 2020, and December 31, 2019, were as follows (in thousands):

	March 31, 2020
	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	$	4	$	109	$	77	$	634	$	81	$	743
REMICs:
GSE	665		135,392		247		24,351		912		159,743
Non-GSE	—		—		2		49		2		49
Other debt securities:
Corporate bonds	1,396		57,948		—		—		1,396		57,948
Total	$	2,065	$	193,449	$	326	$	25,034	$	2,391	$	218,483

	December 31, 2019
	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	$	25	$	3,404	$	729	$	55,184	$	754	$	58,588
REMICs:
GSE	950		197,634		1,275		54,555		2,225		252,189
Non-GSE	—		—		—		53		—		53
Other debt securities:
Corporate bonds	—		—		13		15,586		13		15,586
Total	$	975	$	201,038	$	2,017	$	125,378	$	2,992	$	326,416