Business, Basis of Financial Statement Presentation and Principles of Consolidation - Additional Information (Details)	Mar. 31, 2022 Office
Business Basis Of Financial Statement Presentation And Principles Of Consolidation [Line Items]
Number of offices	179

Business, basis of financial statement presentation and principles of consolidation.

No definition available.

Name:	trmk_BusinessBasisOfFinancialStatementPresentationAndPrinciplesOfConsolidationLineItems
Namespace Prefix:	trmk_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration