Investments (Tables)

6 Months Ended

Jun. 30, 2020

Investments, Debt and Equity Securities [Abstract]

Amortized Cost and Estimated Fair Value of Available-For-Sale Investment Securities

The amortized cost and estimated fair value of available-for-sale investment securities are as follows:

Amortized Cost And Estimated Fair Value

(dollars in thousands, unaudited)

	June 30, 2020
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
U.S. government agencies	$	1,775	$	75	$	—	$	1,850
Mortgage-backed securities		364,828		10,668		(11)		375,485
State and political subdivisions		209,760		12,239		(1)		221,998
Total securities	$	576,363	$	22,982	$	(12)	$	599,333

	December 31, 2019
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
U.S. government agencies	$	12,125	$	124	$	(104)	$	12,145
Mortgage-backed securities		398,353		3,354		(1,318)		400,389
State and political subdivisions		181,900		6,478		(113)		188,265
Total securities	$	592,378	$	9,956	$	(1,535)	$	600,799

Realized Gain (Loss) on Investments

The table below summarizes the Company’s gross realized gains and losses as well as gross proceeds from the sales of securities, for the periods indicated:

Investment Portfolio - Realized Gains/(Losses)

(dollars in thousands, unaudited)

	Three months ended June 30,					Six months ended June 30,
	2020		2019		2020		2019
Proceeds from sales, calls and maturities of securities available for sale	$	24,063	$	9,985	$	26,493	$	26,639
Gross gains on sales, calls and maturities of securities available for sale		433		33		433		127
Gross losses on sales, calls and maturities of securities available for sale		(43)		(11)		(43)		(99)
Net gains on sale of securities available for sale	$	390	$	$22	$	390	$	28

Information Pertaining to Investment Securities Aggregated by Investment Category and Length of Time that Individual Securities in a Continuous Loss Position

Investment Portfolio - Unrealized Losses

(dollars in thousands, unaudited)

	June 30, 2020
	Less than twelve months				Twelve months or more
	Gross Unrealized Losses		Fair Value		Gross Unrealized Losses		Fair Value
U.S. government agencies	$	—	$	—	$	—	$	—
Mortgage-backed securities		(3)		4,692		(8)		1,733
State and political subdivisions		(1)		1,052		—		—
Total	$	(4)	$	5,744	$	(8)	$	1,733

	December 31, 2019
	Less than twelve months				Twelve months or more
	Gross Unrealized Losses		Fair Value		Gross Unrealized Losses		Fair Value
U.S. government agencies	$	(32)	$	3,240	$	(72)	$	2,689
Mortgage-backed securities		(494)		100,518		(824)		78,538
State and political subdivisions		(113)		19,762		—		—
Total	$	(639)	$	123,520	$	(896)	$	81,227

Investments Classified by Contractual Maturity Date

Estimated Fair Value of Contractual Maturities

(dollars in thousands, unaudited)

	June 30, 2020
	Amortized Cost		Fair Value
Maturing within one year	$	4,362	$	4,388
Maturing after one year through five years		7,834		8,104
Maturing after five years through ten years		29,485		30,823
Maturing after ten years		169,854		180,533
Securities not due at a single maturity date:
Mortgage-backed securities		181,945		186,880
Collateralized mortgage obligations		182,883		188,605
	$	576,363	$	599,333

	December 31, 2019
	Amortized Cost		Fair Value
Maturing within one year	$	7,155	$	7,244
Maturing after one year through five years		17,008		17,171
Maturing after five years through ten years		33,805		34,881
Maturing after ten years		136,057		141,114
Securities not due at a single maturity date:
Mortgage-backed securities		189,554		190,488
Collateralized mortgage obligations		208,799		209,901
	$	592,378	$	600,799

Summary of Amortized Cost and Fair Values of General Obligation and Revenue Bonds

The following table summarizes the amortized cost and fair values of general obligation and revenue bonds in the Company’s investment securities portfolio at the indicated dates, identifying the state in which the issuing municipality or agency operates for our largest geographic concentrations:

Revenue and General Obligation Bonds by Location

(dollars in thousands, unaudited)

	June 30, 2020				December 31, 2019
	Amortized		Fair Market		Amortized		Fair Market
General obligation bonds	Cost		Value		Cost		Value
State of issuance
Texas	$	76,494	$	81,128	$	59,439	$	61,519
California		27,447		29,067		23,882		25,030
Washington		23,330		25,023		23,392		24,313
Other (21 & 24 states, respectively)		53,652		56,532		49,326		50,725
Total general obligation bonds		180,923		191,750		156,039		161,587
Revenue bonds
State of issuance
Texas		7,053		7,452		6,035		6,298
Washington		2,256		2,377		1,737		1,856
California		364		382		365		380
Other (15 & 13 states, respectively)		19,164		20,037		17,724		18,144
Total revenue bonds		28,837		30,248		25,861		26,678
Total obligations of states and political subdivisions	$	209,760	$	221,998	$	181,900	$	188,265

The revenue bonds in the Company’s investment securities portfolios were issued by government municipalities and agencies to fund public services such as utilities (water, sewer, and power), educational facilities, and general public and economic improvements. The primary sources of revenue for these bonds are delineated in the table below, which shows the amortized cost and fair market values for the largest revenue concentrations as of the indicated dates.

Revenue Bonds by Type

(dollars in thousands, unaudited)

	June 30, 2020				December 31, 2019
	Amortized		Fair Market		Amortized		Fair Market
Revenue bonds	Cost		Value		Cost		Value
Revenue source:
Water	$	10,363	$	10,949	$	7,515	$	7,775
Sewer		5,219		5,408		4,760		4,811
Sales tax		3,572		3,743		1,949		1,995
Lease		2,773		2,864		3,596		3,678
Charter school aid		1,565		1,689		1,232		1,290
Other (8 and 8 sources, respectively)		5,345		5,595		6,809		7,129
Total revenue bonds	$	28,837	$	30,248	$	25,861	$	26,678