Fair value of loans contractual interest cash flows.

No definition available.

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- Definition

Fair value of loans contractual principal cash flows amount.

+ References

No definition available.

+ Details

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- Definition

Fair value of loans contractual purchase discount.

+ References

No definition available.

+ Details

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- Definition

Fair value of loans future interest payments.

+ References

No definition available.

+ Details

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- Definition

Loan grades range.

+ References

No definition available.

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- Definition

Loans and the allowance for loan losses.

+ References

No definition available.

+ Details

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- Definition

Nonperforming loans charged off past due period.

+ References

No definition available.

+ Details

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Balance Type:	na
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- Definition

Number of Restructured Loans

+ References

No definition available.

+ Details

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Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum duration past due for restructured loans to be considered performing.

+ References

No definition available.

+ Details

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

- Definition

Unfunded commitment.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

- Definition

Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=49124121&loc=d3e5212-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=49124121&loc=d3e5258-111524

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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 Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (g)
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=49124121&loc=SL6953423-111524

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 FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (b)(1)(ii)
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Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 6
-Section L
-Subsection 1

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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=25495931&loc=d3e18794-111554

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Balance Type:	debit
Period Type:	instant

- Definition

The amount of interest income on impaired and nonperforming loans that is due to the change in present value attributable to the passage of time.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 19
-URI http://asc.fasb.org/extlink&oid=49124121&loc=d3e5278-111524

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes loans held for sale. Excludes loans and leases covered under loss sharing agreements.

+ References

Reference 1: 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

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Loans and the Allowance for Loan Losses (Details Textual)	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2015 USD ($) loan loan_grade	Dec. 31, 2014 USD ($) loan	Dec. 31, 2013 USD ($)
Loans and Allowance for Loan Losses (Textual) [Abstract]
Nonperforming Loans Charged Off Past Due Period	90 days
Number of restructured loans \| loan		2	0
Restructured loans discontinued past due period		90 days	90 days
Average recorded investment in impaired loans		$ 127,391,000	$ 164,501,000	$ 123,756,000
Interest income recognized on impaired loans				$ 1,820,000
Allowance for loan losses attributable to restructured loans		42,437,000	42,289,000
Remaining availability under commitments to lend additional funds on restructured loans		0	6,000
Fair value of loans contractual principal cash flows amount		83,078,000	95,081,000
Fair value of loans contractual interest cash flows		241,000	5,499,000
Fair value of loans contractual interest payments		2,312,000	2,798,000
Fair value of loans contractual purchase discount		45,980,000	29,635,000
Unfunded commitment		$ 5,780,000	5,184,000
Maximum
Loans and Allowance for Loan Losses (Textual) [Abstract]
Loan grades range (loan grade) \| loan_grade		9
Minimum
Loans and Allowance for Loan Losses (Textual) [Abstract]
Loan grades range (loan grade) \| loan_grade		1
Pass \| Maximum
Loans and Allowance for Loan Losses (Textual) [Abstract]
Loan grades range (loan grade) \| loan_grade		4
Pass \| Minimum
Loans and Allowance for Loan Losses (Textual) [Abstract]
Loan grades range (loan grade) \| loan_grade		1
Watch
Loans and Allowance for Loan Losses (Textual) [Abstract]
Loan grades range (loan grade) \| loan_grade		5
Substandard \| Maximum
Loans and Allowance for Loan Losses (Textual) [Abstract]
Loan grades range (loan grade) \| loan_grade		9
Substandard \| Minimum
Loans and Allowance for Loan Losses (Textual) [Abstract]
Loan grades range (loan grade) \| loan_grade		6
Nonaccruing Loans
Loans and Allowance for Loan Losses (Textual) [Abstract]
Outstanding balance of restructured loans		$ 314,000	0
Restructured Loans
Loans and Allowance for Loan Losses (Textual) [Abstract]
Outstanding balance of restructured loans		13,517,000	11,392,000
Allowance for loan losses attributable to restructured loans		$ 979,000	$ 1,547,000