Revenue from Contracts with Customers - Summary of Noninterest Income Disaggregated by Reportable Operating Segment and Revenue Stream (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenue From Contract With Customer [Line Items]
Service charges on deposit accounts		$ 33,246	$ 32,289	$ 42,603
Bank card and other fees		34,662	31,022	31,736
Mortgage banking, net		63,750	125,822	29,822
Insurance commissions		48,511	45,176	42,396
Wealth management		35,190	31,625	30,679
Other, net		6,551	8,659	9,809
Total Noninterest Income		221,910	274,593	187,045
Topic 606 [Member]
Revenue From Contract With Customer [Line Items]
Service charges on deposit accounts		33,246	32,289	42,603
Bank card and other fees		30,935	27,428	28,030
Insurance commissions		48,511	45,176	42,396
Wealth management		35,190	31,625	30,679
Other, net		6,856	7,631	9,867
Total Noninterest Income		154,738	144,149	153,575
Not Topic 606 [Member]
Revenue From Contract With Customer [Line Items]
Bank card and other fees	[1]	3,727	3,594	3,706
Mortgage banking, net	[1]	63,750	125,822	29,822
Other, net	[1]	(305)	1,028	(58)
Total Noninterest Income	[1]	67,172	130,444	33,470
General Banking Segment [Member]
Revenue From Contract With Customer [Line Items]
Service charges on deposit accounts		33,169	32,213	42,509
Bank card and other fees		34,624	30,992	31,679
Mortgage banking, net		63,750	125,822	29,822
Wealth management		48	254	379
Other, net		6,283	8,410	9,367
Total Noninterest Income		137,874	197,691	113,756
General Banking Segment [Member] | Topic 606 [Member]
Revenue From Contract With Customer [Line Items]
Service charges on deposit accounts		33,169	32,213	42,509
Bank card and other fees		30,897	27,398	27,973
Wealth management		48	254	379
Other, net		6,621	7,432	9,528
Total Noninterest Income		70,735	67,297	80,389
General Banking Segment [Member] | Not Topic 606 [Member]
Revenue From Contract With Customer [Line Items]
Bank card and other fees	[1]	3,727	3,594	3,706
Mortgage banking, net	[1]	63,750	125,822	29,822
Other, net	[1]	(338)	978	(161)
Total Noninterest Income	[1]	67,139	130,394	33,367
Wealth Management Segment [Member]
Revenue From Contract With Customer [Line Items]
Service charges on deposit accounts		77	76	94
Bank card and other fees		38	30	57
Wealth management		35,142	31,371	30,300
Other, net		163	157	409
Total Noninterest Income		35,420	31,634	30,860
Wealth Management Segment [Member] | Topic 606 [Member]
Revenue From Contract With Customer [Line Items]
Service charges on deposit accounts		77	76	94
Bank card and other fees		38	30	57
Wealth management		35,142	31,371	30,300
Other, net		130	107	306
Total Noninterest Income		35,387	31,584	30,757
Wealth Management Segment [Member] | Not Topic 606 [Member]
Revenue From Contract With Customer [Line Items]
Other, net	[1]	33	50	103
Total Noninterest Income	[1]	33	50	103
Insurance Segment [Member]
Revenue From Contract With Customer [Line Items]
Insurance commissions		48,511	45,176	42,396
Other, net		105	92	33
Total Noninterest Income		48,616	45,268	42,429
Insurance Segment [Member] | Topic 606 [Member]
Revenue From Contract With Customer [Line Items]
Insurance commissions		48,511	45,176	42,396
Other, net		105	92	33
Total Noninterest Income		$ 48,616	$ 45,268	$ 42,429

[1] Noninterest income not in scope for FASB ASC Topic 606 includes customer derivatives revenue and miscellaneous credit card 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 securities gains (losses), net.