Name:	trmk_EstimatedFairValue12MonthsOrMore
Namespace Prefix:	trmk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

No definition available.

Name:	trmk_EstimatedFairValueLessThan12Months
Namespace Prefix:	trmk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

This item represents the excess of amortized cost basis over fair value of securities that have been in a loss position for twelve months or longer for those securities which are categorized as available-for-sale and held-to-maturity securities.

No definition available.

Name:	trmk_GrossUnrealizedLosses12MonthsOrMore
Namespace Prefix:	trmk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

This item represents the excess of amortized cost basis over fair value of securities that have been in a loss position for less than twelve months for those securities which are categorized as available-for-sale and held-to-maturity securities.

No definition available.

Name:	trmk_GrossUnrealizedLossesLessThan12Months
Namespace Prefix:	trmk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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

This item represents the aggregate fair value of investments in an unrealized loss position which are categorized as available-for-sale and held-to-maturity securities.

No definition available.

Name:	trmk_TotalEstimatedFairValue
Namespace Prefix:	trmk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

This item represents the excess of amortized cost basis over fair value of securities in a loss position and which are categorized as available-for-sale and held-to-maturity securities.

No definition available.

Name:	trmk_TotalGrossUnrealizedLosses
Namespace Prefix:	trmk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_USTreasurySecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_FinancialInstrumentAxis=us-gaap_USGovernmentAgenciesDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_FinancialInstrumentAxis=trmk_ResidentialMortgagePassThroughSecuritiesGuaranteedByGNMAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_FinancialInstrumentAxis=trmk_ResidentialMortgagePassThroughSecuritiesIssuedByFNMAAndFHLMCMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_FinancialInstrumentAxis=trmk_OtherResidentialMortgageBackedSecuritiesIssuedOrGuaranteedByFNMAFHLMCOrGNMAMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: