XML 61 R72.htm IDEA: XBRL DOCUMENT v2.4.1.9
Acquired Loans Part 5 (Details) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2014
Dec. 31, 2013
Acquired Loans, Aging [Abstract]    
Current $ 498,236trmk_AcquiredLoansRecordedInvestmentCurrent $ 718,638trmk_AcquiredLoansRecordedInvestmentCurrent
Past Due Greater Than 90 Days 43,412trmk_AcquiredLoansMoreThan90DaysPastDue [1] 63,444trmk_AcquiredLoansMoreThan90DaysPastDue [1]
Nonaccrual 1,144trmk_AcquiredLoansNonaccrualStatus [2] 2,353trmk_AcquiredLoansNonaccrualStatus [2]
Total acquired loans 549,409trmk_AcquiredLoansCarryingValueLoans 804,206trmk_AcquiredLoansCarryingValueLoans
Percentage of risk of losses incurred on acquired covered loans (in hundredths) 20.00%trmk_PercentageOfRiskOfLossesIncurredOnAcquiredLoans 20.00%trmk_PercentageOfRiskOfLossesIncurredOnAcquiredLoans
Noncovered [Member]    
Acquired Loans, Aging [Abstract]    
Current 477,216trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
691,632trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
Past Due Greater Than 90 Days 42,149trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
[1] 60,308trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
[1]
Nonaccrual 1,077trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
[2] 1,867trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
[2]
Total acquired loans 525,783trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
769,990trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
Covered [Member]    
Acquired Loans, Aging [Abstract]    
Current 21,020trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
27,006trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
Past Due Greater Than 90 Days 1,263trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
[1] 3,136trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
[1]
Nonaccrual 67trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
[2] 486trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
[2]
Total acquired loans 23,626trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
34,216trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
Real Estate Secured Financing Receivable [Member] | Construction Land Development And Other Financing Receivable [Member] | Noncovered [Member]    
Acquired Loans, Aging [Abstract]    
Current 35,877trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
65,001trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
Past Due Greater Than 90 Days 21,985trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[1] 31,744trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[1]
Nonaccrual 194trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[2] 67trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[2]
Total acquired loans 58,309trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
98,928trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
Real Estate Secured Financing Receivable [Member] | Construction Land Development And Other Financing Receivable [Member] | Covered [Member]    
Acquired Loans, Aging [Abstract]    
Current 821trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
1,278trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
Past Due Greater Than 90 Days 376trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[1] 553trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[1]
Nonaccrual 0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[2] 445trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[2]
Total acquired loans 1,197trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
2,363trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
Real Estate Secured Financing Receivable [Member] | Secured by 1-4 Family Residential Properties [Member] | Noncovered [Member]    
Acquired Loans, Aging [Abstract]    
Current 107,779trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
145,142trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
Past Due Greater Than 90 Days 5,162trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[1] 7,589trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[1]
Nonaccrual 422trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[2] 116trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[2]
Total acquired loans 116,920trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
157,914trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
Real Estate Secured Financing Receivable [Member] | Secured by 1-4 Family Residential Properties [Member] | Covered [Member]    
Acquired Loans, Aging [Abstract]    
Current 12,154trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
14,401trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
Past Due Greater Than 90 Days 477trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[1] 1,142trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[1]
Nonaccrual 0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[2] 0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[2]
Total acquired loans 13,180trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
16,416trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
Real Estate Secured Financing Receivable [Member] | Nonfarm, Nonresidential Properties [Member] | Noncovered [Member]    
Acquired Loans, Aging [Abstract]    
Current 188,094trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
263,276trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
Past Due Greater Than 90 Days 13,275trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[1] 15,421trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[1]
Nonaccrual 0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[2] 461trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[2]
Total acquired loans 202,323trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
287,136trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
Real Estate Secured Financing Receivable [Member] | Nonfarm, Nonresidential Properties [Member] | Covered [Member]    
Acquired Loans, Aging [Abstract]    
Current 6,945trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
8,247trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
Past Due Greater Than 90 Days 0trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[1] 793trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[1]
Nonaccrual 0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[2] 0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[2]
Total acquired loans 7,672trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
10,945trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
Real Estate Secured Financing Receivable [Member] | Other Real Estate Secured Financing Receivable [Member] | Noncovered [Member]    
Acquired Loans, Aging [Abstract]    
Current 27,209trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
31,953trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
Past Due Greater Than 90 Days 604trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[1] 1,922trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[1]
Nonaccrual 0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[2] 33trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[2]
Total acquired loans 27,813trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
33,948trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
Real Estate Secured Financing Receivable [Member] | Other Real Estate Secured Financing Receivable [Member] | Covered [Member]    
Acquired Loans, Aging [Abstract]    
Current 728trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
1,932trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
Past Due Greater Than 90 Days 368trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[1] 2trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[1]
Nonaccrual 0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[2] 0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[2]
Total acquired loans 1,096trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
2,644trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
Commercial And Industrial Loans Financing Receivable [Member] | Noncovered [Member]    
Acquired Loans, Aging [Abstract]    
Current 86,234trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
144,195trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
Past Due Greater Than 90 Days 1,099trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
[1] 3,387trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
[1]
Nonaccrual 461trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
[2] 1,170trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
[2]
Total acquired loans 88,256trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
149,495trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
Commercial And Industrial Loans Financing Receivable [Member] | Covered [Member]    
Acquired Loans, Aging [Abstract]    
Current 168trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
340trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
Past Due Greater Than 90 Days 42trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
[1] 0trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
[1]
Nonaccrual 67trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
[2] 41trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
[2]
Total acquired loans 277trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
394trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
Consumer Loans Financing Receivable [Member] | Noncovered [Member]    
Acquired Loans, Aging [Abstract]    
Current 9,633trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
18,097trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
Past Due Greater Than 90 Days 24trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
[1] 92trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
[1]
Nonaccrual 0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
[2] 0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
[2]
Total acquired loans 9,772trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
18,428trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
Consumer Loans Financing Receivable [Member] | Covered [Member]    
Acquired Loans, Aging [Abstract]    
Current 0trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
119trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
Past Due Greater Than 90 Days 0trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
[1] 0trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
[1]
Nonaccrual 0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
[2] 0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
[2]
Total acquired loans 0trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
119trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
Other Loans Financing Receivable [Member] | Noncovered [Member]    
Acquired Loans, Aging [Abstract]    
Current 22,390trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
23,968trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
Past Due Greater Than 90 Days 0trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
[1] 153trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
[1]
Nonaccrual 0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
[2] 20trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
[2]
Total acquired loans 22,390trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
24,141trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
Other Loans Financing Receivable [Member] | Covered [Member]    
Acquired Loans, Aging [Abstract]    
Current 204trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
689trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
Past Due Greater Than 90 Days 0trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
[1] 646trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
[1]
Nonaccrual 0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
[2] 0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
[2]
Total acquired loans 204trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
1,335trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
Commercial Portfolio Segment [Member] | Pass [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 320,915trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
433,015trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
Commercial Portfolio Segment [Member] | Pass [Member] | Noncovered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 315,953trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
424,355trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
Commercial Portfolio Segment [Member] | Pass [Member] | Covered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 4,962trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
[3] 8,660trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
[3]
Commercial Portfolio Segment [Member] | Special Mention [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 5,101trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
18,902trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
Commercial Portfolio Segment [Member] | Special Mention [Member] | Noncovered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 4,646trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
18,201trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
Commercial Portfolio Segment [Member] | Special Mention [Member] | Covered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 455trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
[3] 701trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
[3]
Commercial Portfolio Segment [Member] | Substandard [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 108,813trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
186,787trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
Commercial Portfolio Segment [Member] | Substandard [Member] | Noncovered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 103,400trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
177,897trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
Commercial Portfolio Segment [Member] | Substandard [Member] | Covered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 5,413trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
[3] 8,890trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
[3]
Commercial Portfolio Segment [Member] | Doubtful [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 11,931trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_DoubtfulMember
22,494trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_DoubtfulMember
Commercial Portfolio Segment [Member] | Doubtful [Member] | Noncovered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 11,827trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_DoubtfulMember
21,075trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_DoubtfulMember
Commercial Portfolio Segment [Member] | Doubtful [Member] | Covered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 104trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_DoubtfulMember
[3] 1,419trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_DoubtfulMember
[3]
Commercial Portfolio Segment [Member] | Commercial Subtotal [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 446,760trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_InternalCreditAssessmentAxis
= trmk_CommercialSubtotalMember
661,198trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ us-gaap_InternalCreditAssessmentAxis
= trmk_CommercialSubtotalMember
Commercial Portfolio Segment [Member] | Commercial Subtotal [Member] | Noncovered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 435,826trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_InternalCreditAssessmentAxis
= trmk_CommercialSubtotalMember
641,528trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_InternalCreditAssessmentAxis
= trmk_CommercialSubtotalMember
Commercial Portfolio Segment [Member] | Commercial Subtotal [Member] | Covered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 10,934trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_InternalCreditAssessmentAxis
= trmk_CommercialSubtotalMember
[3] 19,670trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_InternalCreditAssessmentAxis
= trmk_CommercialSubtotalMember
[3]
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Construction Land Development And Other Financing Receivable [Member] | Pass [Member] | Noncovered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 20,224trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
39,075trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Construction Land Development And Other Financing Receivable [Member] | Pass [Member] | Covered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 0trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
[3] 228trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
[3]
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Construction Land Development And Other Financing Receivable [Member] | Special Mention [Member] | Noncovered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 280trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
2,506trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Construction Land Development And Other Financing Receivable [Member] | Special Mention [Member] | Covered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 0trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
[3] 0trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
[3]
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Construction Land Development And Other Financing Receivable [Member] | Substandard [Member] | Noncovered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 28,339trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
42,486trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Construction Land Development And Other Financing Receivable [Member] | Substandard [Member] | Covered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 955trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
[3] 1,126trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
[3]
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Construction Land Development And Other Financing Receivable [Member] | Doubtful [Member] | Noncovered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 5,821trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_DoubtfulMember
8,445trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_DoubtfulMember
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Construction Land Development And Other Financing Receivable [Member] | Doubtful [Member] | Covered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 102trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_DoubtfulMember
[3] 771trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_DoubtfulMember
[3]
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Construction Land Development And Other Financing Receivable [Member] | Commercial Subtotal [Member] | Noncovered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 54,664trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= trmk_CommercialSubtotalMember
92,512trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= trmk_CommercialSubtotalMember
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Construction Land Development And Other Financing Receivable [Member] | Commercial Subtotal [Member] | Covered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 1,057trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= trmk_CommercialSubtotalMember
[3] 2,125trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= trmk_CommercialSubtotalMember
[3]
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Secured by 1-4 Family Residential Properties [Member] | Pass [Member] | Noncovered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 30,796trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
33,810trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Secured by 1-4 Family Residential Properties [Member] | Pass [Member] | Covered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 194trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
[3] 1,629trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
[3]
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Secured by 1-4 Family Residential Properties [Member] | Special Mention [Member] | Noncovered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 760trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
2,983trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Secured by 1-4 Family Residential Properties [Member] | Special Mention [Member] | Covered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 235trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
[3] 430trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
[3]
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Secured by 1-4 Family Residential Properties [Member] | Substandard [Member] | Noncovered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 8,466trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
17,422trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Secured by 1-4 Family Residential Properties [Member] | Substandard [Member] | Covered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 1,045trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
[3] 1,798trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
[3]
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Secured by 1-4 Family Residential Properties [Member] | Doubtful [Member] | Noncovered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 388trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_DoubtfulMember
538trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_DoubtfulMember
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Secured by 1-4 Family Residential Properties [Member] | Doubtful [Member] | Covered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 0trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_DoubtfulMember
[3] 0trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_DoubtfulMember
[3]
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Secured by 1-4 Family Residential Properties [Member] | Commercial Subtotal [Member] | Noncovered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 40,410trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= trmk_CommercialSubtotalMember
54,753trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= trmk_CommercialSubtotalMember
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Secured by 1-4 Family Residential Properties [Member] | Commercial Subtotal [Member] | Covered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 1,474trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= trmk_CommercialSubtotalMember
[3] 3,857trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= trmk_CommercialSubtotalMember
[3]
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Nonfarm, Nonresidential Properties [Member] | Pass [Member] | Noncovered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 157,753trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
184,594trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Nonfarm, Nonresidential Properties [Member] | Pass [Member] | Covered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 4,419trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
[3] 5,446trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
[3]
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Nonfarm, Nonresidential Properties [Member] | Special Mention [Member] | Noncovered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 3,452trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
9,027trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Nonfarm, Nonresidential Properties [Member] | Special Mention [Member] | Covered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 88trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
[3] 109trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
[3]
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Nonfarm, Nonresidential Properties [Member] | Substandard [Member] | Noncovered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 39,408trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
88,952trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Nonfarm, Nonresidential Properties [Member] | Substandard [Member] | Covered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 2,879trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
[3] 4,723trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
[3]
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Nonfarm, Nonresidential Properties [Member] | Doubtful [Member] | Noncovered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 1,710trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_DoubtfulMember
4,563trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_DoubtfulMember
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Nonfarm, Nonresidential Properties [Member] | Doubtful [Member] | Covered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 0trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_DoubtfulMember
[3] 0trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_DoubtfulMember
[3]
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Nonfarm, Nonresidential Properties [Member] | Commercial Subtotal [Member] | Noncovered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 202,323trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= trmk_CommercialSubtotalMember
287,136trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= trmk_CommercialSubtotalMember
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Nonfarm, Nonresidential Properties [Member] | Commercial Subtotal [Member] | Covered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 7,386trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= trmk_CommercialSubtotalMember
[3] 10,278trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= trmk_CommercialSubtotalMember
[3]
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Other Real Estate Secured Financing Receivable [Member] | Pass [Member] | Noncovered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 22,754trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
28,156trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Other Real Estate Secured Financing Receivable [Member] | Pass [Member] | Covered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 0trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
[3] 832trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
[3]
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Other Real Estate Secured Financing Receivable [Member] | Special Mention [Member] | Noncovered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 92trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
1,437trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Other Real Estate Secured Financing Receivable [Member] | Special Mention [Member] | Covered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 108trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
[3] 134trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
[3]
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Other Real Estate Secured Financing Receivable [Member] | Substandard [Member] | Noncovered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 4,864trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
4,071trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Other Real Estate Secured Financing Receivable [Member] | Substandard [Member] | Covered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 426trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
[3] 717trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
[3]
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Other Real Estate Secured Financing Receivable [Member] | Doubtful [Member] | Noncovered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 95trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_DoubtfulMember
184trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_DoubtfulMember
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Other Real Estate Secured Financing Receivable [Member] | Doubtful [Member] | Covered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 2trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_DoubtfulMember
[3] 2trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_DoubtfulMember
[3]
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Other Real Estate Secured Financing Receivable [Member] | Commercial Subtotal [Member] | Noncovered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 27,805trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= trmk_CommercialSubtotalMember
33,848trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= trmk_CommercialSubtotalMember
Commercial Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Other Real Estate Secured Financing Receivable [Member] | Commercial Subtotal [Member] | Covered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 536trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= trmk_CommercialSubtotalMember
[3] 1,685trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= trmk_CommercialSubtotalMember
[3]
Commercial Portfolio Segment [Member] | Commercial And Industrial Loans Financing Receivable [Member] | Pass [Member] | Noncovered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 64,720trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
116,818trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
Commercial Portfolio Segment [Member] | Commercial And Industrial Loans Financing Receivable [Member] | Pass [Member] | Covered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 145trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
[3] 254trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
[3]
Commercial Portfolio Segment [Member] | Commercial And Industrial Loans Financing Receivable [Member] | Special Mention [Member] | Noncovered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 17trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
2,248trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
Commercial Portfolio Segment [Member] | Commercial And Industrial Loans Financing Receivable [Member] | Special Mention [Member] | Covered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 24trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
[3] 28trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
[3]
Commercial Portfolio Segment [Member] | Commercial And Industrial Loans Financing Receivable [Member] | Substandard [Member] | Noncovered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 19,706trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
24,084trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
Commercial Portfolio Segment [Member] | Commercial And Industrial Loans Financing Receivable [Member] | Substandard [Member] | Covered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 108trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
[3] 112trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
[3]
Commercial Portfolio Segment [Member] | Commercial And Industrial Loans Financing Receivable [Member] | Doubtful [Member] | Noncovered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 3,813trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_DoubtfulMember
6,039trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_DoubtfulMember
Commercial Portfolio Segment [Member] | Commercial And Industrial Loans Financing Receivable [Member] | Doubtful [Member] | Covered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 0trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_DoubtfulMember
[3] 0trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_DoubtfulMember
[3]
Commercial Portfolio Segment [Member] | Commercial And Industrial Loans Financing Receivable [Member] | Commercial Subtotal [Member] | Noncovered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 88,256trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= trmk_CommercialSubtotalMember
149,189trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= trmk_CommercialSubtotalMember
Commercial Portfolio Segment [Member] | Commercial And Industrial Loans Financing Receivable [Member] | Commercial Subtotal [Member] | Covered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 277trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= trmk_CommercialSubtotalMember
[3] 394trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= trmk_CommercialSubtotalMember
[3]
Commercial Portfolio Segment [Member] | Consumer Loans Financing Receivable [Member] | Pass [Member] | Noncovered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 0trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
21trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
Commercial Portfolio Segment [Member] | Consumer Loans Financing Receivable [Member] | Pass [Member] | Covered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 0trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
[3] 0trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
[3]
Commercial Portfolio Segment [Member] | Consumer Loans Financing Receivable [Member] | Special Mention [Member] | Noncovered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 0trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
0trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
Commercial Portfolio Segment [Member] | Consumer Loans Financing Receivable [Member] | Special Mention [Member] | Covered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 0trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
[3] 0trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
[3]
Commercial Portfolio Segment [Member] | Consumer Loans Financing Receivable [Member] | Substandard [Member] | Noncovered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 0trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
0trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
Commercial Portfolio Segment [Member] | Consumer Loans Financing Receivable [Member] | Substandard [Member] | Covered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 0trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
[3] 0trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
[3]
Commercial Portfolio Segment [Member] | Consumer Loans Financing Receivable [Member] | Doubtful [Member] | Noncovered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 0trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_DoubtfulMember
0trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_DoubtfulMember
Commercial Portfolio Segment [Member] | Consumer Loans Financing Receivable [Member] | Doubtful [Member] | Covered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 0trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_DoubtfulMember
[3] 0trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_DoubtfulMember
[3]
Commercial Portfolio Segment [Member] | Consumer Loans Financing Receivable [Member] | Commercial Subtotal [Member] | Noncovered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 0trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= trmk_CommercialSubtotalMember
21trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= trmk_CommercialSubtotalMember
Commercial Portfolio Segment [Member] | Consumer Loans Financing Receivable [Member] | Commercial Subtotal [Member] | Covered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 0trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= trmk_CommercialSubtotalMember
[3] 0trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= trmk_CommercialSubtotalMember
[3]
Commercial Portfolio Segment [Member] | Other Loans Financing Receivable [Member] | Pass [Member] | Noncovered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 19,706trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
21,881trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
Commercial Portfolio Segment [Member] | Other Loans Financing Receivable [Member] | Pass [Member] | Covered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 204trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
[3] 271trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_PassMember
[3]
Commercial Portfolio Segment [Member] | Other Loans Financing Receivable [Member] | Special Mention [Member] | Noncovered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 45trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
0trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
Commercial Portfolio Segment [Member] | Other Loans Financing Receivable [Member] | Special Mention [Member] | Covered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 0trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
[3] 0trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SpecialMentionMember
[3]
Commercial Portfolio Segment [Member] | Other Loans Financing Receivable [Member] | Substandard [Member] | Noncovered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 2,617trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
882trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
Commercial Portfolio Segment [Member] | Other Loans Financing Receivable [Member] | Substandard [Member] | Covered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 0trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
[3] 414trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_SubstandardMember
[3]
Commercial Portfolio Segment [Member] | Other Loans Financing Receivable [Member] | Doubtful [Member] | Noncovered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 0trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_DoubtfulMember
1,306trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_DoubtfulMember
Commercial Portfolio Segment [Member] | Other Loans Financing Receivable [Member] | Doubtful [Member] | Covered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 0trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_DoubtfulMember
[3] 646trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= us-gaap_DoubtfulMember
[3]
Commercial Portfolio Segment [Member] | Other Loans Financing Receivable [Member] | Commercial Subtotal [Member] | Noncovered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 22,368trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= trmk_CommercialSubtotalMember
24,069trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= trmk_CommercialSubtotalMember
Commercial Portfolio Segment [Member] | Other Loans Financing Receivable [Member] | Commercial Subtotal [Member] | Covered [Member]    
Acquired Loans, Commercial Loans [Abstract]    
Acquired loans 204trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= trmk_CommercialSubtotalMember
[3] 1,331trmk_AcquiredLoansCarryingValue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_CommercialPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
/ us-gaap_InternalCreditAssessmentAxis
= trmk_CommercialSubtotalMember
[3]
Consumer Portfolio Segment [Member]    
Acquired Loans, Aging [Abstract]    
Current 96,194trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
132,901trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
Past Due 30-89 Days 2,947trmk_AcquiredLoans30To89DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
4,793trmk_AcquiredLoans30To89DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
Past Due Greater Than 90 Days 3,391trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
5,205trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
Nonaccrual 117trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
109trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
Subtotal 102,649trmk_AcquiredLoansCarryingValueSubtotal
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
143,008trmk_AcquiredLoansCarryingValueSubtotal
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
Total acquired loans 549,409trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
804,206trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
Consumer Portfolio Segment [Member] | Noncovered [Member]    
Acquired Loans, Aging [Abstract]    
Current 84,318trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
120,354trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
Past Due 30-89 Days 2,474trmk_AcquiredLoans30To89DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
3,946trmk_AcquiredLoans30To89DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
Past Due Greater Than 90 Days 3,048trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
4,053trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
Nonaccrual 117trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
109trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
Subtotal 89,957trmk_AcquiredLoansCarryingValueSubtotal
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
128,462trmk_AcquiredLoansCarryingValueSubtotal
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
Total acquired loans 525,783trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
769,990trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
Consumer Portfolio Segment [Member] | Covered [Member]    
Acquired Loans, Aging [Abstract]    
Current 11,876trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
[3] 12,547trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
[3]
Past Due 30-89 Days 473trmk_AcquiredLoans30To89DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
[3] 847trmk_AcquiredLoans30To89DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
[3]
Past Due Greater Than 90 Days 343trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
[3] 1,152trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
[3]
Nonaccrual 0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
[3] 0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
[3]
Subtotal 12,692trmk_AcquiredLoansCarryingValueSubtotal
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
[3] 14,546trmk_AcquiredLoansCarryingValueSubtotal
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
[3]
Total acquired loans 23,626trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
[3] 34,216trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
[3]
Consumer Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Construction Land Development And Other Financing Receivable [Member] | Noncovered [Member]    
Acquired Loans, Aging [Abstract]    
Current 3,338trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
5,813trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
Past Due 30-89 Days 25trmk_AcquiredLoans30To89DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
108trmk_AcquiredLoans30To89DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
Past Due Greater Than 90 Days 282trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
495trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
Nonaccrual 0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
Subtotal 3,645trmk_AcquiredLoansCarryingValueSubtotal
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
6,416trmk_AcquiredLoansCarryingValueSubtotal
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
Total acquired loans 58,309trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
98,928trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
Consumer Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Construction Land Development And Other Financing Receivable [Member] | Covered [Member]    
Acquired Loans, Aging [Abstract]    
Current 140trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3] 133trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3]
Past Due 30-89 Days 0trmk_AcquiredLoans30To89DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3] 77trmk_AcquiredLoans30To89DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3]
Past Due Greater Than 90 Days 0trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3] 28trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3]
Nonaccrual 0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3] 0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3]
Subtotal 140trmk_AcquiredLoansCarryingValueSubtotal
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3] 238trmk_AcquiredLoansCarryingValueSubtotal
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3]
Total acquired loans 1,197trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3] 2,363trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3]
Consumer Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Secured by 1-4 Family Residential Properties [Member] | Noncovered [Member]    
Acquired Loans, Aging [Abstract]    
Current 71,316trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
95,987trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
Past Due 30-89 Days 2,335trmk_AcquiredLoans30To89DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
3,599trmk_AcquiredLoans30To89DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
Past Due Greater Than 90 Days 2,742trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
3,466trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
Nonaccrual 117trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
109trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
Subtotal 76,510trmk_AcquiredLoansCarryingValueSubtotal
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
103,161trmk_AcquiredLoansCarryingValueSubtotal
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
Total acquired loans 116,920trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
157,914trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
Consumer Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Secured by 1-4 Family Residential Properties [Member] | Covered [Member]    
Acquired Loans, Aging [Abstract]    
Current 10,925trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3] 11,179trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3]
Past Due 30-89 Days 473trmk_AcquiredLoans30To89DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3] 428trmk_AcquiredLoans30To89DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3]
Past Due Greater Than 90 Days 308trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3] 952trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3]
Nonaccrual 0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3] 0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3]
Subtotal 11,706trmk_AcquiredLoansCarryingValueSubtotal
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3] 12,559trmk_AcquiredLoansCarryingValueSubtotal
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3]
Total acquired loans 13,180trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3] 16,416trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_ResidentialFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3]
Consumer Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Nonfarm, Nonresidential Properties [Member] | Noncovered [Member]    
Acquired Loans, Aging [Abstract]    
Current 0trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
0trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
Past Due 30-89 Days 0trmk_AcquiredLoans30To89DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
0trmk_AcquiredLoans30To89DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
Past Due Greater Than 90 Days 0trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
0trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
Nonaccrual 0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
Subtotal 0trmk_AcquiredLoansCarryingValueSubtotal
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
0trmk_AcquiredLoansCarryingValueSubtotal
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
Total acquired loans 202,323trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
287,136trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
Consumer Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Nonfarm, Nonresidential Properties [Member] | Covered [Member]    
Acquired Loans, Aging [Abstract]    
Current 286trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3] 495trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3]
Past Due 30-89 Days 0trmk_AcquiredLoans30To89DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3] 0trmk_AcquiredLoans30To89DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3]
Past Due Greater Than 90 Days 0trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3] 172trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3]
Nonaccrual 0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3] 0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3]
Subtotal 286trmk_AcquiredLoansCarryingValueSubtotal
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3] 667trmk_AcquiredLoansCarryingValueSubtotal
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3]
Total acquired loans 7,672trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3] 10,945trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_NonresidentialPropertiesFinancingReceivablesMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3]
Consumer Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Other Real Estate Secured Financing Receivable [Member] | Noncovered [Member]    
Acquired Loans, Aging [Abstract]    
Current 8trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
100trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
Past Due 30-89 Days 0trmk_AcquiredLoans30To89DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
0trmk_AcquiredLoans30To89DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
Past Due Greater Than 90 Days 0trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
0trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
Nonaccrual 0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
Subtotal 8trmk_AcquiredLoansCarryingValueSubtotal
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
100trmk_AcquiredLoansCarryingValueSubtotal
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
Total acquired loans 27,813trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
33,948trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
Consumer Portfolio Segment [Member] | Real Estate Secured Financing Receivable [Member] | Other Real Estate Secured Financing Receivable [Member] | Covered [Member]    
Acquired Loans, Aging [Abstract]    
Current 525trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3] 617trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3]
Past Due 30-89 Days 0trmk_AcquiredLoans30To89DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3] 342trmk_AcquiredLoans30To89DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3]
Past Due Greater Than 90 Days 35trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3] 0trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3]
Nonaccrual 0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3] 0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3]
Subtotal 560trmk_AcquiredLoansCarryingValueSubtotal
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3] 959trmk_AcquiredLoansCarryingValueSubtotal
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3]
Total acquired loans 1,096trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3] 2,644trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableBySubClassReceivableAxis
= trmk_OtherRealEstateSecuredFinancingReceivableMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_RealEstateSecuredFinancingReceivableMember
[3]
Consumer Portfolio Segment [Member] | Commercial And Industrial Loans Financing Receivable [Member] | Noncovered [Member]    
Acquired Loans, Aging [Abstract]    
Current 0trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
306trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
Past Due 30-89 Days 0trmk_AcquiredLoans30To89DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
0trmk_AcquiredLoans30To89DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
Past Due Greater Than 90 Days 0trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
0trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
Nonaccrual 0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
Subtotal 0trmk_AcquiredLoansCarryingValueSubtotal
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
306trmk_AcquiredLoansCarryingValueSubtotal
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
Total acquired loans 88,256trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
149,495trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
Consumer Portfolio Segment [Member] | Commercial And Industrial Loans Financing Receivable [Member] | Covered [Member]    
Acquired Loans, Aging [Abstract]    
Current 0trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
[3] 0trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
[3]
Past Due 30-89 Days 0trmk_AcquiredLoans30To89DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
[3] 0trmk_AcquiredLoans30To89DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
[3]
Past Due Greater Than 90 Days 0trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
[3] 0trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
[3]
Nonaccrual 0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
[3] 0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
[3]
Subtotal 0trmk_AcquiredLoansCarryingValueSubtotal
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
[3] 0trmk_AcquiredLoansCarryingValueSubtotal
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
[3]
Total acquired loans 277trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
[3] 394trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_CommercialAndIndustrialLoansFinancingReceivableMember
[3]
Consumer Portfolio Segment [Member] | Consumer Loans Financing Receivable [Member] | Noncovered [Member]    
Acquired Loans, Aging [Abstract]    
Current 9,634trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
18,076trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
Past Due 30-89 Days 114trmk_AcquiredLoans30To89DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
239trmk_AcquiredLoans30To89DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
Past Due Greater Than 90 Days 24trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
92trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
Nonaccrual 0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
Subtotal 9,772trmk_AcquiredLoansCarryingValueSubtotal
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
18,407trmk_AcquiredLoansCarryingValueSubtotal
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
Total acquired loans 9,772trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
18,428trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
Consumer Portfolio Segment [Member] | Consumer Loans Financing Receivable [Member] | Covered [Member]    
Acquired Loans, Aging [Abstract]    
Current 0trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
[3] 119trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
[3]
Past Due 30-89 Days 0trmk_AcquiredLoans30To89DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
[3] 0trmk_AcquiredLoans30To89DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
[3]
Past Due Greater Than 90 Days 0trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
[3] 0trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
[3]
Nonaccrual 0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
[3] 0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
[3]
Subtotal 0trmk_AcquiredLoansCarryingValueSubtotal
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
[3] 119trmk_AcquiredLoansCarryingValueSubtotal
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
[3]
Total acquired loans 0trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
[3] 119trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_ConsumerLoansFinancingReceivableMember
[3]
Consumer Portfolio Segment [Member] | Other Loans Financing Receivable [Member] | Noncovered [Member]    
Acquired Loans, Aging [Abstract]    
Current 22trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
72trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
Past Due 30-89 Days 0trmk_AcquiredLoans30To89DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
0trmk_AcquiredLoans30To89DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
Past Due Greater Than 90 Days 0trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
0trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
Nonaccrual 0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
Subtotal 22trmk_AcquiredLoansCarryingValueSubtotal
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
72trmk_AcquiredLoansCarryingValueSubtotal
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
Total acquired loans 22,390trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
24,141trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_NoncoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
Consumer Portfolio Segment [Member] | Other Loans Financing Receivable [Member] | Covered [Member]    
Acquired Loans, Aging [Abstract]    
Current 0trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
[3] 4trmk_AcquiredLoansRecordedInvestmentCurrent
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
[3]
Past Due 30-89 Days 0trmk_AcquiredLoans30To89DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
[3] 0trmk_AcquiredLoans30To89DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
[3]
Past Due Greater Than 90 Days 0trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
[3] 0trmk_AcquiredLoansMoreThan90DaysPastDue
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
[3]
Nonaccrual 0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
[3] 0trmk_AcquiredLoansNonaccrualStatus
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
[3]
Subtotal 0trmk_AcquiredLoansCarryingValueSubtotal
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
[3] 4trmk_AcquiredLoansCarryingValueSubtotal
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
[3]
Total acquired loans $ 204trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
[3] $ 1,335trmk_AcquiredLoansCarryingValueLoans
/ trmk_FinancingReceivableByPortfolioSegmentAxis
= us-gaap_ConsumerPortfolioSegmentMember
/ trmk_FinancingReceivableByTypeAxis
= trmk_CoveredMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= trmk_OtherLoansFinancingReceivableMember
[3]
[1] Past due 90 days or more but still accruing interest.
[2] Acquired loans not accounted for under FASB ASC Topic 310-30.
[3] Total dollar balances are presented in this table; however, these loans are covered by the loss-share agreement with the FDIC. TNB is at risk for only 20% of the losses incurred on these loans.