Securities Available for Sale and Held to Maturity (Tables)

9 Months Ended

Sep. 30, 2020

Investments Debt And Equity Securities [Abstract]

Securities Held to Maturity by Credit Rating, as Determined by Moody's

The following table presents the amortized cost of Trustmark’s securities held to maturity by credit rating, as determined by Moody’s, at September 30, 2020 ($ in thousands):

	September 30, 2020
Aaa	$	579,674
Aa1 to Aa3		26,166
Not Rated (1)		5,440
Total	$	611,280

(1) Not rated securities primarily consist of Mississippi municipal general obligations.

Amortized Cost and Estimated Fair Value of Available for Sale and Held to Maturity Securities

The following tables are a summary of the amortized cost and estimated fair value of securities available for sale and held to maturity at September 30, 2020 and December 31, 2019 ($ in thousands):

	Securities Available for Sale									Securities Held to Maturity
September 30, 2020	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Estimated Fair Value
U.S. Government agency obligations	$	19,318	$	189	$	(496	)	$	19,011	$	—	$	—	$	—		$	—
Obligations of states and political    subdivisions		7,714		601		—			8,315		31,605		375		(12	)		31,968
Mortgage-backed securities
Residential mortgage pass-through    securities
Guaranteed by GNMA		60,492		1,665		(1	)		62,156		8,244		353		—			8,597
Issued by FNMA and FHLMC		1,259,607		21,265		(953	)		1,279,919		78,213		2,776		—			80,989
Other residential mortgage-backed    securities
Issued or guaranteed by FNMA,    FHLMC or GNMA		487,567		13,309		(18	)		500,858		399,400		22,181		(10	)		421,571
Commercial mortgage-backed securities
Issued or guaranteed by FNMA,    FHLMC or GNMA		51,162		1,316		(9	)		52,469		93,818		2,726		(4	)		96,540
Total	$	1,885,860	$	38,345	$	(1,477	)	$	1,922,728	$	611,280	$	28,411	$	(26	)	$	639,665
December 31, 2019
U.S. Government agency obligations	$	22,965	$	69	$	(707	)	$	22,327	$	3,781	$	220	$	—		$	4,001
Obligations of states and political    subdivisions		24,952		513		—			25,465		31,781		434		(53	)		32,162
Mortgage-backed securities
Residential mortgage pass-through    securities
Guaranteed by GNMA		69,196		425		(369	)		69,252		10,820		266		(10	)		11,076
Issued by FNMA and FHLMC		714,350		2,171		(3,165	)		713,356		96,631		286		(370	)		96,547
Other residential mortgage-backed    securities
Issued or guaranteed by FNMA,    FHLMC or GNMA		656,162		3,777		(1,713	)		658,226		485,324		7,026		(656	)		491,694
Commercial mortgage-backed securities
Issued or guaranteed by FNMA,    FHLMC or GNMA		113,359		625		(206	)		113,778		109,762		1,042		(82	)		110,722
Total	$	1,600,984	$	7,580	$	(6,160	)	$	1,602,404	$	738,099	$	9,274	$	(1,171	)	$	746,202

Securities with Gross Unrealized Losses, Segregated by Length of Impairment

The tables below include securities with gross unrealized losses for which an allowance for credit losses has not been recorded and segregated by length of impairment at September 30, 2020 and December 31, 2019 ($ in thousands):

	Less than 12 Months					12 Months or More					Total
September 30, 2020	Estimated Fair Value		Gross Unrealized Losses			Estimated Fair Value		Gross Unrealized Losses			Estimated Fair Value		Gross Unrealized Losses
U.S. Government agency obligations	$	—	$	—		$	11,347	$	(496	)	$	11,347	$	(496	)
Obligations of states and political subdivisions		—		—			6,221		(12	)		6,221		(12	)
Mortgage-backed securities
Residential mortgage pass-through securities
Guaranteed by GNMA		353		(1	)		—		—			353		(1	)
Issued by FNMA and FHLMC		399,494		(953	)		—		—			399,494		(953	)
Other residential mortgage-backed securities
Issued or guaranteed by FNMA, FHLMC or    GNMA		11,155		(28	)		—		—			11,155		(28	)
Commercial mortgage-backed securities
Issued or guaranteed by FNMA, FHLMC or    GNMA		15,029		(4	)		663		(9	)		15,692		(13	)
Total	$	426,031	$	(986	)	$	18,231	$	(517	)	$	444,262	$	(1,503	)
December 31, 2019
U.S. Government agency obligations	$	6,585	$	(105	)	$	12,886	$	(602	)	$	19,471	$	(707	)
Obligations of states and political subdivisions		—		—			6,216		(53	)		6,216		(53	)
Mortgage-backed securities
Residential mortgage pass-through securities
Guaranteed by GNMA		23,544		(107	)		18,529		(272	)		42,073		(379	)
Issued by FNMA and FHLMC		112,879		(230	)		278,120		(3,305	)		390,999		(3,535	)
Other residential mortgage-backed securities
Issued or guaranteed by FNMA, FHLMC or    GNMA		158,341		(738	)		151,271		(1,631	)		309,612		(2,369	)
Commercial mortgage-backed securities
Issued or guaranteed by FNMA, FHLMC or    GNMA		51,312		(167	)		14,155		(121	)		65,467		(288	)
Total	$	352,661	$	(1,347	)	$	481,177	$	(5,984	)	$	833,838	$	(7,331	)

Contractual Maturities of Available for Sale and Held to Maturity Securities

The amortized cost and estimated fair value of securities available for sale and held to maturity at September 30, 2020, by contractual maturity, are shown below ($ in thousands).  Expected maturities may differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties.

	Securities Available for Sale				Securities Held to Maturity
	Amortized Cost		Estimated Fair Value		Amortized Cost		Estimated Fair Value
Due in one year or less	$	4,667	$	4,719	$	20,900	$	21,018
Due after one year through five years		1,543		1,589		10,705		10,950
Due after five years through ten years		2,096		2,051		—		—
Due after ten years		18,726		18,967		—		—
		27,032		27,326		31,605		31,968
Mortgage-backed securities		1,858,828		1,895,402		579,675		607,697
Total	$	1,885,860	$	1,922,728	$	611,280	$	639,665