Amount, excluding accrued interest, of decrease in allowance for credit loss on financing receivable from writeoff. Excludes net investment in lease.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-6

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 13
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-13

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoff
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- References

No definition available.

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestAllowanceForCreditLossWriteoffByOriginationYearAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, excluding accrued interest, of writeoff of financing receivable originated more than five years before current fiscal year. Excludes net investment in lease.

+ References

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestOriginatedMoreThanFiveYearsBeforeCurrentFiscalYearWriteoff
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount, excluding accrued interest, of writeoff of financing receivable that can be withdrawn, repaid, and redrawn.

+ References

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestRevolvingWriteoff
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount, excluding accrued interest, of writeoff of financing receivable originated four years before current fiscal year. Excludes net investment in lease.

+ References

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestYearFiveOriginatedFourYearsBeforeCurrentFiscalYearWriteoff
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount, excluding accrued interest, of writeoff of financing receivable originated three years before current fiscal year. Excludes net investment in lease.

+ References

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestYearFourOriginatedThreeYearsBeforeCurrentFiscalYearWriteoff
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount, excluding accrued interest, of writeoff of financing receivable originated in current fiscal year. Excludes net investment in lease.

+ References

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestYearOneOriginatedCurrentFiscalYearWriteoff
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount, excluding accrued interest, of writeoff of financing receivable originated two years before current fiscal year. Excludes net investment in lease.

+ References

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestYearThreeOriginatedTwoYearsBeforeCurrentFiscalYearWriteoff
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount, excluding accrued interest, of writeoff of financing receivable originated in fiscal year before current fiscal year. Excludes net investment in lease.

+ References

+ Details

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestYearTwoOriginatedFiscalYearBeforeCurrentFiscalYearWriteoff
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_CommercialLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=rnst_LeaseFinancingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_ConstructionLoansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CollateralAxis=us-gaap_ResidentialRealEstateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=rnst_RealEstateOneToFourFamilyMortgageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ParticipatingMortgageLoansAxis=rnst_PrimaryMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ParticipatingMortgageLoansAxis=us-gaap_HomeEquityLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ParticipatingMortgageLoansAxis=rnst_RentalInvestmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=rnst_CommercialResidentialMortgageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ParticipatingMortgageLoansAxis=rnst_OwnerOccupiedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ParticipatingMortgageLoansAxis=rnst_NonownerOccupiedMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ParticipatingMortgageLoansAxis=rnst_LandDevelopmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=rnst_InstallmentLoansToIndividualsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Loans - Gross Charge-Offs (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Current year			$ 6		$ 1,810
Prior year			454		2,301
Two years prior			744		617
Three years prior			75		310
Four years prior			115		725
Prior			7,383		12,412
Revolving Loans			409		865
Total Charge-offs	$ 1,904	$ 3,630	9,186	$ 16,272	19,040
Commercial, financial, agricultural
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Current year			0		898
Prior year			33		1,909
Two years prior			152		235
Three years prior			34		131
Four years prior			4		635
Prior			251		4,165
Revolving Loans			408		865
Total Charge-offs	347	2,252	882	7,720	8,838
Lease financing
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Current year			0		883
Prior year			336		273
Two years prior			306		248
Three years prior			0		72
Four years prior			0		48
Prior			0		0
Revolving Loans			0		0
Total Charge-offs	642	641	642	641	1,524
Real estate – construction:
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Total Charge-offs	0	0		57
Real estate – construction: \| Residential
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Current year					0
Prior year					57
Two years prior					0
Three years prior					0
Four years prior					0
Prior					0
Revolving Loans					0
Total Charge-offs					57
Real estate – 1-4 family mortgage:
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Current year			0		0
Prior year			12		17
Two years prior			186		91
Three years prior			35		72
Four years prior			110		35
Prior			203		202
Revolving Loans			0		0
Total Charge-offs	256	130	546	345	417
Real estate – 1-4 family mortgage: \| Primary
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Current year			0		0
Prior year			12		17
Two years prior			137		0
Three years prior			35		0
Four years prior			110		0
Prior			83		92
Revolving Loans			0		0
Total Charge-offs			377		109
Real estate – 1-4 family mortgage: \| Home equity
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Current year			0		0
Prior year			0		0
Two years prior			49		0
Three years prior			0		0
Four years prior			0		25
Prior			75		90
Revolving Loans			0		0
Total Charge-offs			124		115
Real estate – 1-4 family mortgage: \| Rental/investment
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Current year			0		0
Prior year			0		0
Two years prior			0		91
Three years prior			0		72
Four years prior			0		10
Prior			45		20
Revolving Loans			0		0
Total Charge-offs			45		193
Real Estate - Commercial Mortgage
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Current year			0		0
Prior year			0		0
Two years prior			37		0
Three years prior			0		0
Four years prior			0		0
Prior			5,700		5,568
Revolving Loans			0		0
Total Charge-offs	10	0	5,737	5,512	5,568
Real Estate - Commercial Mortgage \| Owner-occupied
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Current year			0		0
Prior year			0		0
Two years prior			37		0
Three years prior			0		0
Four years prior			0		0
Prior			0		582
Revolving Loans			0		0
Total Charge-offs			37		582
Real Estate - Commercial Mortgage \| Non-owner occupied
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Current year			0		0
Prior year			0		0
Two years prior			0		0
Three years prior			0		0
Four years prior			0		0
Prior			5,693		4,986
Revolving Loans			0		0
Total Charge-offs			5,693		4,986
Real Estate - Commercial Mortgage \| Land development
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Current year			0
Prior year			0
Two years prior			0
Three years prior			0
Four years prior			0
Prior			7
Revolving Loans			0
Total Charge-offs			7
Installment loans to individuals
Financing Receivable, Excluding Accrued Interest, Allowance for Credit Loss, Writeoff, by Origination Year [Abstract]
Current year			6		29
Prior year			73		45
Two years prior			63		43
Three years prior			6		35
Four years prior			1		7
Prior			1,229		2,477
Revolving Loans			1		0
Total Charge-offs	$ 649	$ 607	$ 1,379	$ 1,997	$ 2,636