XML 58 R47.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Securities - Narrative (Details) | 3 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Mar. 31, 2017 USD ($) | Jun. 30, 2018 USD ($) security institution | Dec. 31, 2017 USD ($)
Schedule of Available-for-sale Securities [Line Items] |  |  |
Available for sale debt securities | $ 2,946,000 | $ 1,106,028,000 | $ 674,104,000
Sale proceeds | $ 2,946,000 |  |
Fair Value |  | $ 1,088,779,000 | 671,488,000
Number of institutions issuing debt | institution |  | 160 |
Trust preferred securities |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |
Available for sale debt securities |  | $ 12,402,000 | 12,442,000
Fair Value |  | $ 10,401,000 | 9,388,000
Number of securities representing interests in tranches of trusts (tranches) | security |  | 2 |
Impairments |  | $ 0 |
Secure government, public and trust deposits |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |
Available for sale securities pledged as collateral |  | 443,011,000 | 217,867,000
Short-term borrowings |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |
Available for sale securities pledged as collateral |  | $ 18,278,000 | $ 25,888,000

X
- Definition Number of institutions issuing debt. + References No definition available. + Details
Name: | rnst_NumberOfInstitutionsIssuingDebt
Namespace Prefix: | rnst_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of securities representing interests in tranches of trusts. + References No definition available. + Details
Name: | rnst_NumberOfSecuritiesRepresentingInterestsInTranchesOfTrusts
Namespace Prefix: | rnst_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition This item represents the cost of debt securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.2) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of debt securities categorized neither as held-to-maturity nor trading. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 25 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=75030427&loc=d3e22054-111558 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=82896770&loc=d3e26610-111562 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27161-111563 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 320 -Section 50 -Paragraph 2 -Subparagraph (b)-(g) -URI http://asc.fasb.org/extlink&oid=75019621&loc=d3e62557-112803 + Details
Name: | us-gaap_AvailableForSaleSecuritiesDebtSecurities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The fair value of available-for-sale securities that serve as collateral for borrowings. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 310 -SubTopic 10 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=84173941&loc=d3e5086-111524 + Details
Name: | us-gaap_AvailableForSaleSecuritiesPledgedAsCollateral
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition This element represents the amount of loss recognized for other than temporary impairments (OTTI) of investments in debt and equity securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB TOPIC 5.M) -URI http://asc.fasb.org/extlink&oid=65877573&loc=d3e87990-122713 + Details
Name: | us-gaap_MarketableSecuritiesRealizedGainLossOtherThanTemporaryImpairmentsAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition The cash inflow associated with the sale of debt securities classified as available-for-sale securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=82896770&loc=d3e26853-111562 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 12 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3179-108585 + Details
Name: | us-gaap_ProceedsFromSaleOfAvailableForSaleSecuritiesDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_CashAndCashEquivalentsAxis=rnst_TrustPreferredSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=rnst_SecureGovernmentPublicAndTrustDepositsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=us-gaap_ShortTermDebtMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |