Consumer and other retail loans charged off past due period.

No definition available.

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

- Definition

Fair value of loans contractual interest cash flows.

+ References

No definition available.

+ Details

Name:	rnst_FairValueOfLoansContractualInterestCashFlows
Namespace Prefix:	rnst_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value of loans contractual principal cash flows amount.

+ References

No definition available.

+ Details

Name:	rnst_FairValueOfLoansContractualPrincipalCashFlowsAmount
Namespace Prefix:	rnst_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value of loans future interest payments.

+ References

No definition available.

+ Details

Name:	rnst_FairValueOfLoansFutureInterestPayments
Namespace Prefix:	rnst_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Interest income recognized.

+ References

No definition available.

+ Details

Name:	rnst_InterestIncomeRecognized
Namespace Prefix:	rnst_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Loan grades range.

+ References

No definition available.

+ Details

Name:	rnst_LoanGradesRange
Namespace Prefix:	rnst_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	rnst_LoansAndAllowanceForLoanLossesAdditionalTextualAbstract
Namespace Prefix:	rnst_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	rnst_LoansAndAllowanceForLoanLossesTextualAbstract
Namespace Prefix:	rnst_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Mortgage and commercial loans discontinued past due period.

+ References

No definition available.

+ Details

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

- Definition

Nonperforming loans charged-off past due period.

+ References

No definition available.

+ Details

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

- Definition

Restructured loans discontinued past due period.

+ References

No definition available.

+ Details

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

- Definition

Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 5

-Paragraph 8, 9

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph (b)(1)(ii)

-URI http://asc.fasb.org/extlink&oid=6379141&loc=d3e15032-111544

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.7(d))

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher OTS

-Name Federal Regulation (FR)

-Number Title 12

-Section 563c.102

-Paragraph 8

-Subparagraph a(ii)

-Chapter V

-Subsection I

-LegacyDoc This is a non-GAAP reference that was included in the 2009 taxonomy. It will be removed from future versions of this taxonomy.

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 7

-Subparagraph d

-Article 9

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 114

-Paragraph 20

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Staff Accounting Bulletin (SAB)

-Number Topic 6

-Section L

-Subsection 1

+ Details

Name:	us-gaap_LoansAndLeasesReceivableAllowance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Reflects the unfunded portion of contractual agreements to lend funds to borrowers for loans whose terms have been modified by troubled debt restructuring.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 40

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6951948&loc=d3e18794-111554

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 15

-Paragraph 40

-Subparagraph b.

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

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

- Definition

Total of loans held-for-sale and held-in-portfolio net of unearned income, allowance for loan and lease losses, if any, unamortized loan origination and other fees and costs, and purchased premiums or discounts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 7

-Subparagraph a

-Article 9

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.7(a))

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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

Loans and the Allowance for Loan Losses (Details Textual) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011
Loans and Allowance for Loan Losses (Textual) [Abstract]
Allowance for loan losses	$ 44,069		$ 44,069		$ 44,340
Outstanding balance of restructured loans	2,756,094		2,756,094		2,536,744
Loans and Allowance for Loan Losses (Additional Textual) [Abstract]
Mortgage and commercial loans discontinued past due period			90 days
Consumer and other retail loans charged-off past due period			120 days
Interest income recognized using the cash-basis method of income recognition	814	500	1,128	891
Remaining availability under commitments to lend additional funds on restructured loans	288		288		194
Fair value of loans contractual principal cash flows amount	33,747		33,747
Fair value of loans contractual interest cash flows	11,469		11,469
Fair value of loans contractual interest payments	3,773		5,362
Restructured loans discontinued past due period			90 days		90 days
Nonperforming loans charged-off past due period			90 days
Watch [Member]
Loans and Allowance for Loan Losses (Textual) [Abstract]
Loan grades range			5
Maximum [Member]
Loans and Allowance for Loan Losses (Textual) [Abstract]
Loan grades range			9
Maximum [Member] \| Pass [Member]
Loans and Allowance for Loan Losses (Textual) [Abstract]
Loan grades range			4
Maximum [Member] \| Substandard [Member]
Loans and Allowance for Loan Losses (Textual) [Abstract]
Loan grades range			9
Minimum [Member]
Loans and Allowance for Loan Losses (Textual) [Abstract]
Loan grades range			1
Minimum [Member] \| Pass [Member]
Loans and Allowance for Loan Losses (Textual) [Abstract]
Loan grades range			1
Minimum [Member] \| Substandard [Member]
Loans and Allowance for Loan Losses (Textual) [Abstract]
Loan grades range			6
Restructured Loans [Member]
Loans and Allowance for Loan Losses (Textual) [Abstract]
Allowance for loan losses	5,211		5,211		5,994
Outstanding balance of restructured loans	$ 4,011		$ 4,011		$ 2,295