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Acquired Loans Part 6 (Details) (USD $) In Thousands, unless otherwise specified | Dec. 31, 2014 | Dec. 31, 2013
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Acquired Loans, Aging [Abstract] |  |  |  |
Past Due 30 - 59 Days | $ 3,823 trmk_AcquiredLoans30To59DaysPastDue |  | $ 12,600 trmk_AcquiredLoans30To59DaysPastDue |
Past Due 60 - 89 Days | 2,794 trmk_AcquiredLoans60To89DaysPastDue |  | 7,171 trmk_AcquiredLoans60To89DaysPastDue |
Past Due Greater Than 90 Days | 43,412 trmk_AcquiredLoansMoreThan90DaysPastDue | [1] | 63,444 trmk_AcquiredLoansMoreThan90DaysPastDue | [1]
Total Past Due | 50,029 trmk_AcquiredLoansCarryingValueTotalPastDue |  | 83,215 trmk_AcquiredLoansCarryingValueTotalPastDue |
Nonaccrual | 1,144 trmk_AcquiredLoansNonaccrualStatus | [2] | 2,353 trmk_AcquiredLoansNonaccrualStatus | [2]
Current Loans | 498,236 trmk_AcquiredLoansRecordedInvestmentCurrent |  | 718,638 trmk_AcquiredLoansRecordedInvestmentCurrent |
Acquired loans | 549,409 trmk_AcquiredLoansCarryingValueLoans |  | 804,206 trmk_AcquiredLoansCarryingValueLoans |
Noncovered [Member] |  |  |  |
Acquired Loans, Aging [Abstract] |  |  |  |
Past Due 30 - 59 Days | 3,331 trmk_AcquiredLoans30To59DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember |  | 11,171 trmk_AcquiredLoans30To59DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember |
Past Due 60 - 89 Days | 2,010 trmk_AcquiredLoans60To89DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember |  | 5,012 trmk_AcquiredLoans60To89DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember |
Past Due Greater Than 90 Days | 42,149 trmk_AcquiredLoansMoreThan90DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember | [1] | 60,308 trmk_AcquiredLoansMoreThan90DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember | [1]
Total Past Due | 47,490 trmk_AcquiredLoansCarryingValueTotalPastDue / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember |  | 76,491 trmk_AcquiredLoansCarryingValueTotalPastDue / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember |
Nonaccrual | 1,077 trmk_AcquiredLoansNonaccrualStatus / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember | [2] | 1,867 trmk_AcquiredLoansNonaccrualStatus / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember | [2]
Current Loans | 477,216 trmk_AcquiredLoansRecordedInvestmentCurrent / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember |  | 691,632 trmk_AcquiredLoansRecordedInvestmentCurrent / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember |
Acquired loans | 525,783 trmk_AcquiredLoansCarryingValueLoans / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember |  | 769,990 trmk_AcquiredLoansCarryingValueLoans / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember |
Covered [Member] |  |  |  |
Acquired Loans, Aging [Abstract] |  |  |  |
Past Due 30 - 59 Days | 492 trmk_AcquiredLoans30To59DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember |  | 1,429 trmk_AcquiredLoans30To59DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember |
Past Due 60 - 89 Days | 784 trmk_AcquiredLoans60To89DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember |  | 2,159 trmk_AcquiredLoans60To89DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember |
Past Due Greater Than 90 Days | 1,263 trmk_AcquiredLoansMoreThan90DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember | [1] | 3,136 trmk_AcquiredLoansMoreThan90DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember | [1]
Total Past Due | 2,539 trmk_AcquiredLoansCarryingValueTotalPastDue / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember |  | 6,724 trmk_AcquiredLoansCarryingValueTotalPastDue / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember |
Nonaccrual | 67 trmk_AcquiredLoansNonaccrualStatus / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember | [2] | 486 trmk_AcquiredLoansNonaccrualStatus / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember | [2]
Current Loans | 21,020 trmk_AcquiredLoansRecordedInvestmentCurrent / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember |  | 27,006 trmk_AcquiredLoansRecordedInvestmentCurrent / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember |
Acquired loans | 23,626 trmk_AcquiredLoansCarryingValueLoans / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember |  | 34,216 trmk_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] |  |  |  |
Past Due 30 - 59 Days | 246 trmk_AcquiredLoans30To59DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |  | 1,648 trmk_AcquiredLoans30To59DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |
Past Due 60 - 89 Days | 7 trmk_AcquiredLoans60To89DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |  | 468 trmk_AcquiredLoans60To89DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |
Past Due Greater Than 90 Days | 21,985 trmk_AcquiredLoansMoreThan90DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember | [1] | 31,744 trmk_AcquiredLoansMoreThan90DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember | [1]
Total Past Due | 22,238 trmk_AcquiredLoansCarryingValueTotalPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |  | 33,860 trmk_AcquiredLoansCarryingValueTotalPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |
Nonaccrual | 194 trmk_AcquiredLoansNonaccrualStatus / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember | [2] | 67 trmk_AcquiredLoansNonaccrualStatus / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember | [2]
Current Loans | 35,877 trmk_AcquiredLoansRecordedInvestmentCurrent / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |  | 65,001 trmk_AcquiredLoansRecordedInvestmentCurrent / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |
Acquired loans | 58,309 trmk_AcquiredLoansCarryingValueLoans / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |  | 98,928 trmk_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] |  |  |  |
Past Due 30 - 59 Days | 0 trmk_AcquiredLoans30To59DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |  | 87 trmk_AcquiredLoans30To59DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |
Past Due 60 - 89 Days | 0 trmk_AcquiredLoans60To89DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |  | 0 trmk_AcquiredLoans60To89DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |
Past Due Greater Than 90 Days | 376 trmk_AcquiredLoansMoreThan90DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember | [1] | 553 trmk_AcquiredLoansMoreThan90DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember | [1]
Total Past Due | 376 trmk_AcquiredLoansCarryingValueTotalPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |  | 640 trmk_AcquiredLoansCarryingValueTotalPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |
Nonaccrual | 0 trmk_AcquiredLoansNonaccrualStatus / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember | [2] | 445 trmk_AcquiredLoansNonaccrualStatus / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember | [2]
Current Loans | 821 trmk_AcquiredLoansRecordedInvestmentCurrent / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |  | 1,278 trmk_AcquiredLoansRecordedInvestmentCurrent / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |
Acquired loans | 1,197 trmk_AcquiredLoansCarryingValueLoans / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ConstructionLandDevelopmentAndOtherFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |  | 2,363 trmk_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] |  |  |  |
Past Due 30 - 59 Days | 2,576 trmk_AcquiredLoans30To59DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ResidentialFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |  | 3,901 trmk_AcquiredLoans30To59DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ResidentialFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |
Past Due 60 - 89 Days | 981 trmk_AcquiredLoans60To89DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ResidentialFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |  | 1,166 trmk_AcquiredLoans60To89DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ResidentialFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |
Past Due Greater Than 90 Days | 5,162 trmk_AcquiredLoansMoreThan90DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ResidentialFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember | [1] | 7,589 trmk_AcquiredLoansMoreThan90DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ResidentialFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember | [1]
Total Past Due | 8,719 trmk_AcquiredLoansCarryingValueTotalPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ResidentialFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |  | 12,656 trmk_AcquiredLoansCarryingValueTotalPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ResidentialFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |
Nonaccrual | 422 trmk_AcquiredLoansNonaccrualStatus / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ResidentialFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember | [2] | 116 trmk_AcquiredLoansNonaccrualStatus / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ResidentialFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember | [2]
Current Loans | 107,779 trmk_AcquiredLoansRecordedInvestmentCurrent / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ResidentialFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |  | 145,142 trmk_AcquiredLoansRecordedInvestmentCurrent / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ResidentialFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |
Acquired loans | 116,920 trmk_AcquiredLoansCarryingValueLoans / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ResidentialFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |  | 157,914 trmk_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] |  |  |  |
Past Due 30 - 59 Days | 253 trmk_AcquiredLoans30To59DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ResidentialFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |  | 515 trmk_AcquiredLoans30To59DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ResidentialFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |
Past Due 60 - 89 Days | 296 trmk_AcquiredLoans60To89DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ResidentialFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |  | 358 trmk_AcquiredLoans60To89DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ResidentialFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |
Past Due Greater Than 90 Days | 477 trmk_AcquiredLoansMoreThan90DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ResidentialFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember | [1] | 1,142 trmk_AcquiredLoansMoreThan90DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ResidentialFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember | [1]
Total Past Due | 1,026 trmk_AcquiredLoansCarryingValueTotalPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ResidentialFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |  | 2,015 trmk_AcquiredLoansCarryingValueTotalPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ResidentialFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |
Nonaccrual | 0 trmk_AcquiredLoansNonaccrualStatus / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ResidentialFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember | [2] | 0 trmk_AcquiredLoansNonaccrualStatus / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ResidentialFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember | [2]
Current Loans | 12,154 trmk_AcquiredLoansRecordedInvestmentCurrent / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ResidentialFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |  | 14,401 trmk_AcquiredLoansRecordedInvestmentCurrent / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ResidentialFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |
Acquired loans | 13,180 trmk_AcquiredLoansCarryingValueLoans / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_ResidentialFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |  | 16,416 trmk_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] |  |  |  |
Past Due 30 - 59 Days | 89 trmk_AcquiredLoans30To59DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_NonresidentialPropertiesFinancingReceivablesMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |  | 4,851 trmk_AcquiredLoans30To59DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_NonresidentialPropertiesFinancingReceivablesMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |
Past Due 60 - 89 Days | 865 trmk_AcquiredLoans60To89DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_NonresidentialPropertiesFinancingReceivablesMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |  | 3,127 trmk_AcquiredLoans60To89DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_NonresidentialPropertiesFinancingReceivablesMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |
Past Due Greater Than 90 Days | 13,275 trmk_AcquiredLoansMoreThan90DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_NonresidentialPropertiesFinancingReceivablesMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember | [1] | 15,421 trmk_AcquiredLoansMoreThan90DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_NonresidentialPropertiesFinancingReceivablesMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember | [1]
Total Past Due | 14,229 trmk_AcquiredLoansCarryingValueTotalPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_NonresidentialPropertiesFinancingReceivablesMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |  | 23,399 trmk_AcquiredLoansCarryingValueTotalPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_NonresidentialPropertiesFinancingReceivablesMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |
Nonaccrual | 0 trmk_AcquiredLoansNonaccrualStatus / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_NonresidentialPropertiesFinancingReceivablesMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember | [2] | 461 trmk_AcquiredLoansNonaccrualStatus / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_NonresidentialPropertiesFinancingReceivablesMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember | [2]
Current Loans | 188,094 trmk_AcquiredLoansRecordedInvestmentCurrent / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_NonresidentialPropertiesFinancingReceivablesMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |  | 263,276 trmk_AcquiredLoansRecordedInvestmentCurrent / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_NonresidentialPropertiesFinancingReceivablesMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |
Acquired loans | 202,323 trmk_AcquiredLoansCarryingValueLoans / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_NonresidentialPropertiesFinancingReceivablesMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |  | 287,136 trmk_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] |  |  |  |
Past Due 30 - 59 Days | 239 trmk_AcquiredLoans30To59DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_NonresidentialPropertiesFinancingReceivablesMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |  | 243 trmk_AcquiredLoans30To59DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_NonresidentialPropertiesFinancingReceivablesMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |
Past Due 60 - 89 Days | 488 trmk_AcquiredLoans60To89DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_NonresidentialPropertiesFinancingReceivablesMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |  | 1,662 trmk_AcquiredLoans60To89DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_NonresidentialPropertiesFinancingReceivablesMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |
Past Due Greater Than 90 Days | 0 trmk_AcquiredLoansMoreThan90DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_NonresidentialPropertiesFinancingReceivablesMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember | [1] | 793 trmk_AcquiredLoansMoreThan90DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_NonresidentialPropertiesFinancingReceivablesMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember | [1]
Total Past Due | 727 trmk_AcquiredLoansCarryingValueTotalPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_NonresidentialPropertiesFinancingReceivablesMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |  | 2,698 trmk_AcquiredLoansCarryingValueTotalPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_NonresidentialPropertiesFinancingReceivablesMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |
Nonaccrual | 0 trmk_AcquiredLoansNonaccrualStatus / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_NonresidentialPropertiesFinancingReceivablesMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember | [2] | 0 trmk_AcquiredLoansNonaccrualStatus / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_NonresidentialPropertiesFinancingReceivablesMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember | [2]
Current Loans | 6,945 trmk_AcquiredLoansRecordedInvestmentCurrent / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_NonresidentialPropertiesFinancingReceivablesMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |  | 8,247 trmk_AcquiredLoansRecordedInvestmentCurrent / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_NonresidentialPropertiesFinancingReceivablesMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |
Acquired loans | 7,672 trmk_AcquiredLoansCarryingValueLoans / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_NonresidentialPropertiesFinancingReceivablesMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |  | 10,945 trmk_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] |  |  |  |
Past Due 30 - 59 Days | 0 trmk_AcquiredLoans30To59DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_OtherRealEstateSecuredFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |  | 40 trmk_AcquiredLoans30To59DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_OtherRealEstateSecuredFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |
Past Due 60 - 89 Days | 0 trmk_AcquiredLoans60To89DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_OtherRealEstateSecuredFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |  | 0 trmk_AcquiredLoans60To89DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_OtherRealEstateSecuredFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |
Past Due Greater Than 90 Days | 604 trmk_AcquiredLoansMoreThan90DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_OtherRealEstateSecuredFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember | [1] | 1,922 trmk_AcquiredLoansMoreThan90DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_OtherRealEstateSecuredFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember | [1]
Total Past Due | 604 trmk_AcquiredLoansCarryingValueTotalPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_OtherRealEstateSecuredFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |  | 1,962 trmk_AcquiredLoansCarryingValueTotalPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_OtherRealEstateSecuredFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |
Nonaccrual | 0 trmk_AcquiredLoansNonaccrualStatus / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_OtherRealEstateSecuredFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember | [2] | 33 trmk_AcquiredLoansNonaccrualStatus / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_OtherRealEstateSecuredFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember | [2]
Current Loans | 27,209 trmk_AcquiredLoansRecordedInvestmentCurrent / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_OtherRealEstateSecuredFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |  | 31,953 trmk_AcquiredLoansRecordedInvestmentCurrent / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_OtherRealEstateSecuredFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |
Acquired loans | 27,813 trmk_AcquiredLoansCarryingValueLoans / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_OtherRealEstateSecuredFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |  | 33,948 trmk_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] |  |  |  |
Past Due 30 - 59 Days | 0 trmk_AcquiredLoans30To59DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_OtherRealEstateSecuredFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |  | 571 trmk_AcquiredLoans30To59DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_OtherRealEstateSecuredFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |
Past Due 60 - 89 Days | 0 trmk_AcquiredLoans60To89DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_OtherRealEstateSecuredFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |  | 139 trmk_AcquiredLoans60To89DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_OtherRealEstateSecuredFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |
Past Due Greater Than 90 Days | 368 trmk_AcquiredLoansMoreThan90DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_OtherRealEstateSecuredFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember | [1] | 2 trmk_AcquiredLoansMoreThan90DaysPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_OtherRealEstateSecuredFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember | [1]
Total Past Due | 368 trmk_AcquiredLoansCarryingValueTotalPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_OtherRealEstateSecuredFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |  | 712 trmk_AcquiredLoansCarryingValueTotalPastDue / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_OtherRealEstateSecuredFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |
Nonaccrual | 0 trmk_AcquiredLoansNonaccrualStatus / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_OtherRealEstateSecuredFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember | [2] | 0 trmk_AcquiredLoansNonaccrualStatus / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_OtherRealEstateSecuredFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember | [2]
Current Loans | 728 trmk_AcquiredLoansRecordedInvestmentCurrent / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_OtherRealEstateSecuredFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |  | 1,932 trmk_AcquiredLoansRecordedInvestmentCurrent / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_OtherRealEstateSecuredFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |
Acquired loans | 1,096 trmk_AcquiredLoansCarryingValueLoans / trmk_FinancingReceivableBySubClassReceivableAxis = trmk_OtherRealEstateSecuredFinancingReceivableMember / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_RealEstateSecuredFinancingReceivableMember |  | 2,644 trmk_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] |  |  |  |
Past Due 30 - 59 Days | 334 trmk_AcquiredLoans30To59DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_CommercialAndIndustrialLoansFinancingReceivableMember |  | 526 trmk_AcquiredLoans30To59DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_CommercialAndIndustrialLoansFinancingReceivableMember |
Past Due 60 - 89 Days | 128 trmk_AcquiredLoans60To89DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_CommercialAndIndustrialLoansFinancingReceivableMember |  | 217 trmk_AcquiredLoans60To89DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_CommercialAndIndustrialLoansFinancingReceivableMember |
Past Due Greater Than 90 Days | 1,099 trmk_AcquiredLoansMoreThan90DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_CommercialAndIndustrialLoansFinancingReceivableMember | [1] | 3,387 trmk_AcquiredLoansMoreThan90DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_CommercialAndIndustrialLoansFinancingReceivableMember | [1]
Total Past Due | 1,561 trmk_AcquiredLoansCarryingValueTotalPastDue / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_CommercialAndIndustrialLoansFinancingReceivableMember |  | 4,130 trmk_AcquiredLoansCarryingValueTotalPastDue / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_CommercialAndIndustrialLoansFinancingReceivableMember |
Nonaccrual | 461 trmk_AcquiredLoansNonaccrualStatus / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_CommercialAndIndustrialLoansFinancingReceivableMember | [2] | 1,170 trmk_AcquiredLoansNonaccrualStatus / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_CommercialAndIndustrialLoansFinancingReceivableMember | [2]
Current Loans | 86,234 trmk_AcquiredLoansRecordedInvestmentCurrent / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_CommercialAndIndustrialLoansFinancingReceivableMember |  | 144,195 trmk_AcquiredLoansRecordedInvestmentCurrent / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_CommercialAndIndustrialLoansFinancingReceivableMember |
Acquired loans | 88,256 trmk_AcquiredLoansCarryingValueLoans / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_CommercialAndIndustrialLoansFinancingReceivableMember |  | 149,495 trmk_AcquiredLoansCarryingValueLoans / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_CommercialAndIndustrialLoansFinancingReceivableMember |
Commercial And Industrial Loans Financing Receivable [Member] | Covered [Member] |  |  |  |
Acquired Loans, Aging [Abstract] |  |  |  |
Past Due 30 - 59 Days | 0 trmk_AcquiredLoans30To59DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_CommercialAndIndustrialLoansFinancingReceivableMember |  | 13 trmk_AcquiredLoans30To59DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_CommercialAndIndustrialLoansFinancingReceivableMember |
Past Due 60 - 89 Days | 0 trmk_AcquiredLoans60To89DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_CommercialAndIndustrialLoansFinancingReceivableMember |  | 0 trmk_AcquiredLoans60To89DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_CommercialAndIndustrialLoansFinancingReceivableMember |
Past Due Greater Than 90 Days | 42 trmk_AcquiredLoansMoreThan90DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_CommercialAndIndustrialLoansFinancingReceivableMember | [1] | 0 trmk_AcquiredLoansMoreThan90DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_CommercialAndIndustrialLoansFinancingReceivableMember | [1]
Total Past Due | 42 trmk_AcquiredLoansCarryingValueTotalPastDue / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_CommercialAndIndustrialLoansFinancingReceivableMember |  | 13 trmk_AcquiredLoansCarryingValueTotalPastDue / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_CommercialAndIndustrialLoansFinancingReceivableMember |
Nonaccrual | 67 trmk_AcquiredLoansNonaccrualStatus / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_CommercialAndIndustrialLoansFinancingReceivableMember | [2] | 41 trmk_AcquiredLoansNonaccrualStatus / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_CommercialAndIndustrialLoansFinancingReceivableMember | [2]
Current Loans | 168 trmk_AcquiredLoansRecordedInvestmentCurrent / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_CommercialAndIndustrialLoansFinancingReceivableMember |  | 340 trmk_AcquiredLoansRecordedInvestmentCurrent / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_CommercialAndIndustrialLoansFinancingReceivableMember |
Acquired loans | 277 trmk_AcquiredLoansCarryingValueLoans / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_CommercialAndIndustrialLoansFinancingReceivableMember |  | 394 trmk_AcquiredLoansCarryingValueLoans / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_CommercialAndIndustrialLoansFinancingReceivableMember |
Consumer Loans Financing Receivable [Member] | Noncovered [Member] |  |  |  |
Acquired Loans, Aging [Abstract] |  |  |  |
Past Due 30 - 59 Days | 86 trmk_AcquiredLoans30To59DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_ConsumerLoansFinancingReceivableMember |  | 205 trmk_AcquiredLoans30To59DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_ConsumerLoansFinancingReceivableMember |
Past Due 60 - 89 Days | 29 trmk_AcquiredLoans60To89DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_ConsumerLoansFinancingReceivableMember |  | 34 trmk_AcquiredLoans60To89DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_ConsumerLoansFinancingReceivableMember |
Past Due Greater Than 90 Days | 24 trmk_AcquiredLoansMoreThan90DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_ConsumerLoansFinancingReceivableMember | [1] | 92 trmk_AcquiredLoansMoreThan90DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_ConsumerLoansFinancingReceivableMember | [1]
Total Past Due | 139 trmk_AcquiredLoansCarryingValueTotalPastDue / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_ConsumerLoansFinancingReceivableMember |  | 331 trmk_AcquiredLoansCarryingValueTotalPastDue / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_ConsumerLoansFinancingReceivableMember |
Nonaccrual | 0 trmk_AcquiredLoansNonaccrualStatus / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_ConsumerLoansFinancingReceivableMember | [2] | 0 trmk_AcquiredLoansNonaccrualStatus / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_ConsumerLoansFinancingReceivableMember | [2]
Current Loans | 9,633 trmk_AcquiredLoansRecordedInvestmentCurrent / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_ConsumerLoansFinancingReceivableMember |  | 18,097 trmk_AcquiredLoansRecordedInvestmentCurrent / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_ConsumerLoansFinancingReceivableMember |
Acquired loans | 9,772 trmk_AcquiredLoansCarryingValueLoans / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_ConsumerLoansFinancingReceivableMember |  | 18,428 trmk_AcquiredLoansCarryingValueLoans / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_ConsumerLoansFinancingReceivableMember |
Consumer Loans Financing Receivable [Member] | Covered [Member] |  |  |  |
Acquired Loans, Aging [Abstract] |  |  |  |
Past Due 30 - 59 Days | 0 trmk_AcquiredLoans30To59DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_ConsumerLoansFinancingReceivableMember |  | 0 trmk_AcquiredLoans30To59DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_ConsumerLoansFinancingReceivableMember |
Past Due 60 - 89 Days | 0 trmk_AcquiredLoans60To89DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_ConsumerLoansFinancingReceivableMember |  | 0 trmk_AcquiredLoans60To89DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_ConsumerLoansFinancingReceivableMember |
Past Due Greater Than 90 Days | 0 trmk_AcquiredLoansMoreThan90DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_ConsumerLoansFinancingReceivableMember | [1] | 0 trmk_AcquiredLoansMoreThan90DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_ConsumerLoansFinancingReceivableMember | [1]
Total Past Due | 0 trmk_AcquiredLoansCarryingValueTotalPastDue / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_ConsumerLoansFinancingReceivableMember |  | 0 trmk_AcquiredLoansCarryingValueTotalPastDue / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_ConsumerLoansFinancingReceivableMember |
Nonaccrual | 0 trmk_AcquiredLoansNonaccrualStatus / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_ConsumerLoansFinancingReceivableMember | [2] | 0 trmk_AcquiredLoansNonaccrualStatus / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_ConsumerLoansFinancingReceivableMember | [2]
Current Loans | 0 trmk_AcquiredLoansRecordedInvestmentCurrent / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_ConsumerLoansFinancingReceivableMember |  | 119 trmk_AcquiredLoansRecordedInvestmentCurrent / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_ConsumerLoansFinancingReceivableMember |
Acquired loans | 0 trmk_AcquiredLoansCarryingValueLoans / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_ConsumerLoansFinancingReceivableMember |  | 119 trmk_AcquiredLoansCarryingValueLoans / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_ConsumerLoansFinancingReceivableMember |
Other Loans Financing Receivable [Member] | Noncovered [Member] |  |  |  |
Acquired Loans, Aging [Abstract] |  |  |  |
Past Due 30 - 59 Days | 0 trmk_AcquiredLoans30To59DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_OtherLoansFinancingReceivableMember |  | 0 trmk_AcquiredLoans30To59DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_OtherLoansFinancingReceivableMember |
Past Due 60 - 89 Days | 0 trmk_AcquiredLoans60To89DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_OtherLoansFinancingReceivableMember |  | 0 trmk_AcquiredLoans60To89DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_OtherLoansFinancingReceivableMember |
Past Due Greater Than 90 Days | 0 trmk_AcquiredLoansMoreThan90DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_OtherLoansFinancingReceivableMember | [1] | 153 trmk_AcquiredLoansMoreThan90DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_OtherLoansFinancingReceivableMember | [1]
Total Past Due | 0 trmk_AcquiredLoansCarryingValueTotalPastDue / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_OtherLoansFinancingReceivableMember |  | 153 trmk_AcquiredLoansCarryingValueTotalPastDue / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_OtherLoansFinancingReceivableMember |
Nonaccrual | 0 trmk_AcquiredLoansNonaccrualStatus / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_OtherLoansFinancingReceivableMember | [2] | 20 trmk_AcquiredLoansNonaccrualStatus / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_OtherLoansFinancingReceivableMember | [2]
Current Loans | 22,390 trmk_AcquiredLoansRecordedInvestmentCurrent / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_OtherLoansFinancingReceivableMember |  | 23,968 trmk_AcquiredLoansRecordedInvestmentCurrent / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_OtherLoansFinancingReceivableMember |
Acquired loans | 22,390 trmk_AcquiredLoansCarryingValueLoans / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_OtherLoansFinancingReceivableMember |  | 24,141 trmk_AcquiredLoansCarryingValueLoans / trmk_FinancingReceivableByTypeAxis = trmk_NoncoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_OtherLoansFinancingReceivableMember |
Other Loans Financing Receivable [Member] | Covered [Member] |  |  |  |
Acquired Loans, Aging [Abstract] |  |  |  |
Past Due 30 - 59 Days | 0 trmk_AcquiredLoans30To59DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_OtherLoansFinancingReceivableMember |  | 0 trmk_AcquiredLoans30To59DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_OtherLoansFinancingReceivableMember |
Past Due 60 - 89 Days | 0 trmk_AcquiredLoans60To89DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_OtherLoansFinancingReceivableMember |  | 0 trmk_AcquiredLoans60To89DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_OtherLoansFinancingReceivableMember |
Past Due Greater Than 90 Days | 0 trmk_AcquiredLoansMoreThan90DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_OtherLoansFinancingReceivableMember | [1] | 646 trmk_AcquiredLoansMoreThan90DaysPastDue / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_OtherLoansFinancingReceivableMember | [1]
Total Past Due | 0 trmk_AcquiredLoansCarryingValueTotalPastDue / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_OtherLoansFinancingReceivableMember |  | 646 trmk_AcquiredLoansCarryingValueTotalPastDue / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_OtherLoansFinancingReceivableMember |
Nonaccrual | 0 trmk_AcquiredLoansNonaccrualStatus / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_OtherLoansFinancingReceivableMember | [2] | 0 trmk_AcquiredLoansNonaccrualStatus / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_OtherLoansFinancingReceivableMember | [2]
Current Loans | 204 trmk_AcquiredLoansRecordedInvestmentCurrent / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_OtherLoansFinancingReceivableMember |  | 689 trmk_AcquiredLoansRecordedInvestmentCurrent / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_OtherLoansFinancingReceivableMember |
Acquired loans | $ 204 trmk_AcquiredLoansCarryingValueLoans / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_OtherLoansFinancingReceivableMember |  | $ 1,335 trmk_AcquiredLoansCarryingValueLoans / trmk_FinancingReceivableByTypeAxis = trmk_CoveredMember / us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis = trmk_OtherLoansFinancingReceivableMember |
[1] | Past due 90 days or more but still accruing interest.
[2] | Acquired loans not accounted for under FASB ASC Topic 310-30.

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