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, 2022		Jun. 30, 2021		Jun. 30, 2022		Jun. 30, 2021
Revenue From Contract With Customer [Line Items]
Service charges on deposit accounts	$ 10,226		$ 7,613		$ 19,677		$ 14,969
Bank card and other fees	10,167		8,301		18,609		17,773
Mortgage banking, net	8,149		17,333		18,022		38,137
Insurance commissions	13,702		12,217		27,791		24,662
Wealth management	9,102		8,946		18,156		17,362
Other, net	1,907		2,001		5,113		4,091
Total Noninterest Income	53,253		56,411		107,368		116,994
Topic 606 [Member]
Revenue From Contract With Customer [Line Items]
Service charges on deposit accounts	10,226		7,613		19,677		14,969
Bank card and other fees	8,677		8,529		16,104		15,721
Insurance commissions	13,702		12,217		27,791		24,662
Wealth management	9,102		8,946		18,156		17,362
Other, net	1,895		1,741		4,437		3,184
Total Noninterest Income	43,602		39,046		86,165		75,898
Not Topic 606 [Member
Revenue From Contract With Customer [Line Items]
Bank card and other fees	1,490	[1]	(228)	[1]	2,505	[2]	2,052	[2]
Mortgage banking, net	8,149	[1]	17,333	[1]	18,022	[2]	38,137	[2]
Other, net	12	[1]	260	[1]	676	[2]	907	[2]
Total Noninterest Income	9,651	[1]	17,365	[1]	21,203	[2]	41,096	[2]
General Banking Segment [Member]
Revenue From Contract With Customer [Line Items]
Service charges on deposit accounts	10,205		7,591		19,636		14,929
Bank card and other fees	10,155		8,291		18,587		17,755
Mortgage banking, net	8,149		17,333		18,022		38,137
Wealth management	181		2		205		20
Other, net	1,855		1,950		5,030		3,978
Total Noninterest Income	30,545		35,167		61,480		74,819
General Banking Segment [Member] | Topic 606 [Member]
Revenue From Contract With Customer [Line Items]
Service charges on deposit accounts	10,205		7,591		19,636		14,929
Bank card and other fees	8,665		8,519		16,082		15,703
Wealth management	181		2		205		20
Other, net	1,855		1,699		4,373		3,087
Total Noninterest Income	20,906		17,811		40,296		33,739
General Banking Segment [Member] | Not Topic 606 [Member
Revenue From Contract With Customer [Line Items]
Bank card and other fees	1,490	[1]	(228)	[1]	2,505	[2]	2,052	[2]
Mortgage banking, net	8,149	[1]	17,333	[1]	18,022	[2]	38,137	[2]
Other, net			251	[1]	657	[2]	891	[2]
Total Noninterest Income	9,639	[1]	17,356	[1]	21,184	[2]	41,080	[2]
Wealth Management Segment [Member]
Revenue From Contract With Customer [Line Items]
Service charges on deposit accounts	21		22		41		40
Bank card and other fees	12		10		22		18
Wealth management	8,921		8,944		17,951		17,342
Other, net	45		44		84		83
Total Noninterest Income	8,999		9,020		18,098		17,483
Wealth Management Segment [Member] | Topic 606 [Member]
Revenue From Contract With Customer [Line Items]
Service charges on deposit accounts	21		22		41		40
Bank card and other fees	12		10		22		18
Wealth management	8,921		8,944		17,951		17,342
Other, net	33		35		65		67
Total Noninterest Income	8,987		9,011		18,079		17,467
Wealth Management Segment [Member] | Not Topic 606 [Member
Revenue From Contract With Customer [Line Items]
Other, net	12	[1]	9	[1]	19	[2]	16	[2]
Total Noninterest Income	12	[1]	9	[1]	19	[2]	16	[2]
Insurance Segment [Member]
Revenue From Contract With Customer [Line Items]
Insurance commissions	13,702		12,217		27,791		24,662
Other, net	7		7		(1)		30
Total Noninterest Income	13,709		12,224		27,790		24,692
Insurance Segment [Member] | Topic 606 [Member]
Revenue From Contract With Customer [Line Items]
Insurance commissions	13,702		12,217		27,791		24,662
Other, net	7		7		(1)		30
Total Noninterest Income	$ 13,709		$ 12,224		$ 27,790		$ 24,692

[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.

[2] 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.