Regulatory Matters - Guidelines Governing the Classification of Capital Tiers (Details)	Jun. 30, 2025
Banking and Thrift, Interest [Abstract]
Tier 1 Capital to Average Assets (Leverage), Well capitalized	0.05
Tier 1 Capital to Average Assets (Leverage), Adequately capitalized	0.04
Tier 1 Capital to Average Assets (Leverage), Undercapitalized	4.00%
Tier 1 Capital to Average Assets (Leverage), Significantly undercapitalized	3.00%
Common Equity Tier 1 to Risk-Weighted Assets, Well capitalized	6.50%
Common Equity Tier 1 to Risk-Weighted Assets, Adequately capitalized	4.50%
Common Equity Tier 1 to Risk-Weighted Assets, Undercapitalized	4.50%
Common Equity Tier 1 to Risk-Weighted Assets, Significantly undercapitalized	3.00%
Tier 1 Capital to Risk-Weighted Assets, Well capitalized	0.08
Tier 1 Capital to Risk-Weighted Assets, Adequately capitalized	0.06
Tier 1 Capital to Risk-Weighted Assets, Undercapitalized	6.00%
Tier 1 Capital to Risk-Weighted Assets, Significantly undercapitalized	4.00%
Total Capital to Risk-Weighted Assets, Well capitalized	0.10
Total Capital to Risk-Weighted Assets, Adequately capitalized	0.08
Total Capital to Risk-Weighted Assets, Undercapitalized	8.00%
Total Capital to Risk-Weighted Assets, Significantly undercapitalized	6.00%
Critically undercapitalized	2.00%

Capital Required to be Significantly Undercapitalized to Risk Weighted Assets

No definition available.

Name:	rnst_CapitalRequiredtobeSignificantlyUndercapitalizedtoRiskWeightedAssets
Namespace Prefix:	rnst_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Capital Required to be Undercapitalized to Risk Weighted Assets

+ References

No definition available.

+ Details

Name:	rnst_CapitalRequiredtobeUndercapitalizedtoRiskWeightedAssets
Namespace Prefix:	rnst_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Common Equity Tier One Leverage Capital Required For Capital Adequacy To Average Assets

+ References

No definition available.

+ Details

Name:	rnst_CommonEquityTierOneLeverageCapitalRequiredForCapitalAdequacyToAverageAssets
Namespace Prefix:	rnst_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Common Equity Tier One Leverage Capital Required To Be Significantly Undercapitalized to Average Assets

+ References

No definition available.

+ Details

Name:	rnst_CommonEquityTierOneLeverageCapitalRequiredToBeSignificantlyUndercapitalizedtoAverageAssets
Namespace Prefix:	rnst_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Common Equity Tier One Leverage Capital Required To Be Undercapitalized To Average Assets

+ References

No definition available.

+ Details

Name:	rnst_CommonEquityTierOneLeverageCapitalRequiredToBeUndercapitalizedToAverageAssets
Namespace Prefix:	rnst_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Common Equity Tier One Leverage Capital To Average Assets

+ References

No definition available.

+ Details

Name:	rnst_CommonEquityTierOneLeverageCapitalRequiredToBeWellCapitalizedToAverageAssets
Namespace Prefix:	rnst_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Tangible Capital Required to be Critically Undercapitalized to Total Assets

+ References

No definition available.

+ Details

Name:	rnst_TangibleCapitalRequiredtobeCriticallyUndercapitalizedtoTotalAssets
Namespace Prefix:	rnst_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Tier One Leverage Capital Required to be Significantly Undercapitalized to Average Assets

+ References

No definition available.

+ Details

Name:	rnst_TierOneLeverageCapitalRequiredtobeSignificantlyUndercapitalizedtoAverageAssets
Namespace Prefix:	rnst_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Tier One Leverage Capital Required to be Undercapitalized to Average Assets

+ References

No definition available.

+ Details

Name:	rnst_TierOneLeverageCapitalRequiredtobeUndercapitalizedtoAverageAssets
Namespace Prefix:	rnst_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Tier One Risk Based Capital Required to be Significantly Undercapitalized to Risk Weighted Assets

+ References

No definition available.

+ Details

Name:	rnst_TierOneRiskBasedCapitalRequiredtobeSignificantlyUndercapitalizedtoRiskWeightedAssets
Namespace Prefix:	rnst_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Tier One Risk Based Capital Required to be Undercapitalized to Risk Weighted Assets

+ References

No definition available.

+ Details

Name:	rnst_TierOneRiskBasedCapitalRequiredtobeUndercapitalizedtoRiskWeightedAssets
Namespace Prefix:	rnst_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- References

No definition available.

+ Details

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

- Definition

Ratio of minimum total risk-based capital to risk-weighted assets required for capital adequacy as defined by regulatory framework.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 505
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477270/942-505-50-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 505
-Name Accounting Standards Codification
-Section 50
-Paragraph 1B
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147477270/942-505-50-1B

+ Details

Name:	us-gaap_CapitalRequiredForCapitalAdequacyToRiskWeightedAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Ratio of minimum total risk-based capital to risk-weighted assets categorized as well capitalized as defined by regulatory framework for prompt corrective action.

+ References

+ Details

Name:	us-gaap_CapitalRequiredToBeWellCapitalizedToRiskWeightedAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Ratio of minimum Tier 1 leverage capital to average assets required for capital adequacy as defined by regulatory framework.

+ References

+ Details

Name:	us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacyToAverageAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Ratio of minimum Tier 1 leverage capital to average assets categorized as well capitalized as defined by regulatory framework for prompt corrective action.

+ References

+ Details

Name:	us-gaap_TierOneLeverageCapitalRequiredToBeWellCapitalizedToAverageAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Ratio of minimum Tier 1 risk-based capital to risk-weighted assets required for capital adequacy as defined by regulatory framework.

+ References

+ Details

Name:	us-gaap_TierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Ratio of minimum Tier 1 risk-based capital to risk-weighted assets categorized as well capitalized as defined by regulatory framework for prompt corrective action.

+ References

+ Details

Name:	us-gaap_TierOneRiskBasedCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant