Revenue from Contracts with Customers - Summary of Noninterest Income Disaggregated by Reportable Operating Segment and Revenue Stream (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2024	Mar. 31, 2023
Revenue From Contract With Customer [Line Items]
Service charges on deposit accounts		$ 10,958	$ 10,336
Bank card and other fees		7,428	7,803
Mortgage banking, net		8,915	7,639
Insurance commissions		15,464	14,305
Wealth management		8,952	8,780
Other, net		3,632	2,514
Total Noninterest Income		55,349	51,377
Topic 606 [Member]
Revenue From Contract With Customer [Line Items]
Service charges on deposit accounts		10,958	10,336
Bank card and other fees		7,228	7,654
Insurance commissions		15,464	14,305
Wealth management		8,952	8,780
Other, net		3,920	3,027
Total Noninterest Income		46,522	44,102
Not Topic 606 [Member
Revenue From Contract With Customer [Line Items]
Bank card and other fees	[1]	200	149
Mortgage banking, net	[1]	8,915	7,639
Other, net	[1]	(288)	(513)
Total Noninterest Income	[1]	8,827	7,275
General Banking Segment [Member]
Revenue From Contract With Customer [Line Items]
Service charges on deposit accounts		10,936	10,315
Bank card and other fees		7,392	7,792
Mortgage banking, net		8,915	7,639
Wealth management		189	233
Other, net		2,966	2,380
Total Noninterest Income		30,398	28,359
General Banking Segment [Member] | Topic 606 [Member]
Revenue From Contract With Customer [Line Items]
Service charges on deposit accounts		10,936	10,315
Bank card and other fees		7,192	7,643
Wealth management		189	233
Other, net		3,348	2,988
Total Noninterest Income		21,665	21,179
General Banking Segment [Member] | Not Topic 606 [Member
Revenue From Contract With Customer [Line Items]
Bank card and other fees	[1]	200	149
Mortgage banking, net	[1]	8,915	7,639
Other, net	[1]	(382)	(608)
Total Noninterest Income	[1]	8,733	7,180
Wealth Management Segment [Member]
Revenue From Contract With Customer [Line Items]
Service charges on deposit accounts		22	21
Bank card and other fees		36	11
Wealth management		8,763	8,547
Other, net		136	140
Total Noninterest Income		8,957	8,719
Wealth Management Segment [Member] | Topic 606 [Member]
Revenue From Contract With Customer [Line Items]
Service charges on deposit accounts		22	21
Bank card and other fees		36	11
Wealth management		8,763	8,547
Other, net		42	45
Total Noninterest Income		8,863	8,624
Wealth Management Segment [Member] | Not Topic 606 [Member
Revenue From Contract With Customer [Line Items]
Other, net	[1]	94	95
Total Noninterest Income	[1]	94	95
Insurance Segment [Member]
Revenue From Contract With Customer [Line Items]
Insurance commissions		15,464	14,305
Other, net		530	(6)
Total Noninterest Income		15,994	14,299
Insurance Segment [Member] | Topic 606 [Member]
Revenue From Contract With Customer [Line Items]
Insurance commissions		15,464	14,305
Other, net		530	(6)
Total Noninterest Income		15,994	14,299
Insurance Segment [Member] | Not Topic 606 [Member
Revenue From Contract With Customer [Line Items]
Total Noninterest Income	[1]	$ 0	$ 0

[1] Noninterest income not in scope for FASB ASC Topic 606 includes customer derivatives revenue and miscellaneous credit card fee income within bank card and other fees; mortgage banking, net; amortization of tax credits, accretion of the FDIC indemnification asset, cash surrender value on various life insurance policies, earnings on Trustmark’s non-qualified deferred compensation plans, other partnership investments and rental income within other, net; and security gains (losses), net.