Securities (Tables)

12 Months Ended

Dec. 31, 2019

Investments Debt And Equity Securities [Abstract]

Summary of Carrying Amount and Fair Value of Securities

The carrying amount of securities and their approximate fair values are reflected in the following table:

December 31, 2019	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
US treasury securities	$	4,988	$	27	$	—	$	5,015
US government agencies		22,444		335		—		22,779
Mortgage-backed securities		488,694		15,530		927		503,297
Municipal bonds		8,493		469		8		8,954
Total	$	524,619	$	16,361	$	935	$	540,045
December 31, 2018
US treasury securities	$	4,969	$	—	$	3	$	4,966
US government agencies		31,121		48		225		30,944
Mortgage-backed securities		345,606		1,340		3,365		343,581
Municipal bond		1,000		—		1		999
Total	$	382,696	$	1,388	$	3,594	$	380,490

Gross Unrealized Losses and Fair Value of Securities in a Continuous Unrealized Loss Position

The following tables show gross unrealized losses and fair value, aggregated by investment category and length of time that the individual securities have been in a continuous unrealized loss position.

	Less Than 12 Months				12 Months or More				Total
December 31, 2019	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
Mortgage-backed securities	$	42,835	$	460	$	36,518	$	467	$	79,353	$	927
Municipal bonds		—		—		92		8		92		8
Total	$	42,835	$	460	$	36,610	$	475	$	79,445	$	935

	Less Than 12 Months				12 Months or More				Total
December 31, 2018	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
US treasury securities	$	4,966	$	3	$	—	$	—	$	4,966	$	3
US government agencies		—		—		16,268		225		16,268		225
Mortgage-backed securities		164,836		1,177		51,371		2,188		216,207		3,365
Municipal bond		999		1		—		—		999		1
Total	$	170,801	$	1,181	$	67,639	$	2,413	$	238,440	$	3,594

Summary of Investment Securities by Maturity

The following is a summary of investment securities by maturity:

	December 31, 2019
	Available-for-sale
	Amortized cost		Fair value
US treasury securities
Within one year	$	4,988	$	5,015
Total		4,988		5,015
US government agencies
Within one year		7,008		7,052
One to five years		12,520		12,673
Five to ten years		2,916		3,054
Total		22,444		22,779
Mortgage-backed securities
One to five years		5,030		5,131
Five to ten years		152,561		159,082
After 10 years		331,103		339,084
Total		488,694		503,297
Municipal bonds
After 10 years		8,493		8,954
Total		8,493		8,954
Total	$	524,619	$	540,045