Revenue from Contracts with Customers - Summary of Noninterest Income Disaggregated by Reportable Operating Segment and Revenue Stream (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Revenue From Contract With Customer [Line Items]
Service charges on deposit accounts		$ 10,695	$ 10,226	$ 21,031	$ 19,677
Bank card and other fees		8,917	10,167	16,720	18,609
Mortgage banking, net		6,600	8,149	14,239	18,022
Insurance commissions		14,764	13,702	29,069	27,791
Wealth management		8,882	9,102	17,662	18,156
Other, net		3,695	1,907	6,209	5,113
Total Noninterest Income		53,553	53,253	104,930	107,368
Topic 606 [Member]
Revenue From Contract With Customer [Line Items]
Service charges on deposit accounts		10,695	10,226	21,031	19,677
Bank card and other fees		8,049	8,677	15,703	16,104
Insurance commissions		14,764	13,702	29,069	27,791
Wealth management		8,882	9,102	17,662	18,156
Other, net		3,928	1,895	6,955	4,437
Total Noninterest Income		46,318	43,602	90,420	86,165
Not Topic 606 [Member
Revenue From Contract With Customer [Line Items]
Bank card and other fees	[1]	868	1,490	1,017	2,505
Mortgage banking, net	[1]	6,600	8,149	14,239	18,022
Other, net	[1]	(233)	12	(746)	676
Total Noninterest Income	[1]	7,235	9,651	14,510	21,203
General Banking Segment [Member]
Revenue From Contract With Customer [Line Items]
Service charges on deposit accounts		10,673	10,205	20,988	19,636
Bank card and other fees		8,904	10,155	16,696	18,587
Mortgage banking, net		6,600	8,149	14,239	18,022
Wealth management		215	181	448	205
Other, net		2,603	1,855	4,983	5,030
Total Noninterest Income		28,995	30,545	57,354	61,480
General Banking Segment [Member] | Topic 606 [Member]
Revenue From Contract With Customer [Line Items]
Service charges on deposit accounts		10,673	10,205	20,988	19,636
Bank card and other fees		8,036	8,665	15,679	16,082
Wealth management		215	181	448	205
Other, net		2,932	1,855	5,920	4,373
Total Noninterest Income		21,856	20,906	43,035	40,296
General Banking Segment [Member] | Not Topic 606 [Member
Revenue From Contract With Customer [Line Items]
Bank card and other fees	[1]	868	1,490	1,017	2,505
Mortgage banking, net	[1]	6,600	8,149	14,239	18,022
Other, net	[1]	(329)		(937)	657
Total Noninterest Income	[1]	7,139	9,639	14,319	21,184
Wealth Management Segment [Member]
Revenue From Contract With Customer [Line Items]
Service charges on deposit accounts		22	21	43	41
Bank card and other fees		13	12	24	22
Wealth management		8,667	8,921	17,214	17,951
Other, net		132	45	272	84
Total Noninterest Income		8,834	8,999	17,553	18,098
Wealth Management Segment [Member] | Topic 606 [Member]
Revenue From Contract With Customer [Line Items]
Service charges on deposit accounts		22	21	43	41
Bank card and other fees		13	12	24	22
Wealth management		8,667	8,921	17,214	17,951
Other, net		36	33	81	65
Total Noninterest Income		8,738	8,987	17,362	18,079
Wealth Management Segment [Member] | Not Topic 606 [Member
Revenue From Contract With Customer [Line Items]
Other, net	[1]	96	12	191	19
Total Noninterest Income	[1]	96	12	191	19
Insurance Segment [Member]
Revenue From Contract With Customer [Line Items]
Insurance commissions		14,764	13,702	29,069	27,791
Other, net		960	7	954	(1)
Total Noninterest Income		15,724	13,709	30,023	27,790
Insurance Segment [Member] | Topic 606 [Member]
Revenue From Contract With Customer [Line Items]
Insurance commissions		14,764	13,702	29,069	27,791
Other, net		960	7	954	(1)
Total Noninterest Income		$ 15,724	13,709	$ 30,023	27,790
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.