Allowance for Credit Losses - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Receivables [Abstract]
Interest receivable	$ 52,202		$ 49,850
Deferred interest, allowance for credit loss	1,248		$ 1,248
Provision for credit losses on loans	$ 7,960	$ 1,500
Supportable period	2 years

Deferred Interest, Allowance for Credit Loss

No definition available.

Name:	rnst_DeferredInterestAllowanceForCreditLoss
Namespace Prefix:	rnst_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Financing Receivable, Credit Loss Expense Supportable Period

+ References

No definition available.

+ Details

Name:	rnst_FinancingReceivableCreditLossExpenseSupportablePeriod
Namespace Prefix:	rnst_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Carrying amount as of the balance sheet date of interest earned but not received. Also called accrued interest or accrued interest receivable.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(3)(a)(4))
-URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_InterestReceivable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of credit loss expense (reversal of expense) for financing receivable.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 20
-Section 50
-Paragraph 13
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=124255953&loc=SL82919249-210447

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 220
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(11))
-URI https://asc.fasb.org/extlink&oid=120399700&loc=SL114874048-224260

+ Details

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

- References

No definition available.

+ Details

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