Segment Information - Schedule of Segment Information (Details) - USD ($) $ in Thousands		3 Months Ended				6 Months Ended
		Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Segment Reporting Information [Line Items]
Net interest income		$ 119,423		$ 105,000		$ 221,759	$ 208,952
Provision for credit losses	[1]	537		24,427		(19,331)	51,791
Noninterest income		56,411		69,511		116,994	134,775
Noninterest expense	[1]	118,679		112,417		240,227	229,444
Income Before Income Taxes		56,618		37,667		117,857	62,492
Income taxes		8,637		5,517		17,914	8,124
Net Income		47,981	$ 51,962	32,150	$ 22,218	99,943	54,368
Selected Financial Information
Total assets		17,098,132		15,692,079		17,098,132	15,692,079	$ 16,551,840
Depreciation and amortization		11,302		10,660		22,428	19,656
General Banking [Member]
Segment Reporting Information [Line Items]
Net interest income		118,169		103,376		219,277	205,779
Provision for credit losses	[1]	540		24,430		(19,326)	49,587
Noninterest income		35,167		50,051		74,819	95,227
Noninterest expense	[1]	102,199		97,113		206,163	196,780
Income Before Income Taxes		50,597		31,884		107,259	54,639
Income taxes		7,137		4,093		15,260	6,184
Net Income		43,460		27,791		91,999	48,455
Selected Financial Information
Total assets		16,716,574		15,378,653		16,716,574	15,378,653
Depreciation and amortization		11,046		10,422		21,910	19,216
Wealth Management [Member]
Segment Reporting Information [Line Items]
Net interest income		1,256		1,576		2,487	3,080
Provision for credit losses		(3)		(3)		(5)	2,204
Noninterest income		9,020		7,550		17,483	16,066
Noninterest expense		7,749		6,944		15,943	15,460
Income Before Income Taxes		2,530		2,185		4,032	1,482
Income taxes		633		547		1,009	371
Net Income		1,897		1,638		3,023	1,111
Selected Financial Information
Total assets		299,275		232,467		299,275	232,467
Depreciation and amortization		66		67		134	134
Insurance [Member]
Segment Reporting Information [Line Items]
Net interest income		(2)		48		(5)	93
Noninterest income		12,224		11,910		24,692	23,482
Noninterest expense		8,731		8,360		18,121	17,204
Income Before Income Taxes		3,491		3,598		6,566	6,371
Income taxes		867		877		1,645	1,569
Net Income		2,624		2,721		4,921	4,802
Selected Financial Information
Total assets		82,283		80,959		82,283	80,959
Depreciation and amortization		$ 190		$ 171		$ 384	$ 306

[1] During the second quarter of 2021, Trustmark reclassified its credit loss expense related to off-balance sheet credit exposures from noninterest expense to provision for credit losses, off-balance sheet credit exposures. Prior periods have been reclassified accordingly