XML 153 R133.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Derivatives (Derivatives Associated With Cash Flow Hedges) (Details) - Cash Flow Hedge - Hedging Instruments And Hedged Items - USD ($) $ in Thousands | Dec. 31, 2017 | Mar. 31, 2017 | Dec. 31, 2016 | Mar. 31, 2016
--- | --- | --- | --- | ---
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Variability in cash flows related to debt instruments (primarily loans) |  | $ 650,000 |  | $ 250,000
Interest Rate Contract |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Variability in cash flows related to debt instruments (primarily loans) | $ 900,000 |  | $ 250,000 |
Interest Rate Swap |  |  |  |
Derivative Instruments, Gain (Loss) [Line Items] |  |  |  |
Notional | 900,000 |  | 250,000 |
Cash Flow Hedge Derivative Instrument Assets at Fair Value | $ 942 |  |  |
Liabilities |  |  | $ 2,045 |

X
- Definition Held-to-maturity trust preferred loans. + References No definition available. + Details
Name: | fhn_HeldToMaturityTrustPreferredLoansPrincipalBalance
Namespace Prefix: | fhn_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Aggregate notional amount specified by the derivative(s). Expressed as an absolute value. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Article 12 -Section 13 -Sentence Column B + Details
Name: | invest_DerivativeNotionalAmount
Namespace Prefix: | invest_
Data Type: | xbrli:monetaryItemType
Balance Type: | na
Period Type: | instant

X
- Definition Fair value of all asset derivatives designated as cash flow hedging instruments. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4B -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624163-113959 + Details
Name: | us-gaap_CashFlowHedgeDerivativeInstrumentAssetsAtFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value of all liability derivatives designated as cash flow hedging instruments. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4B -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624163-113959 + Details
Name: | us-gaap_CashFlowHedgeDerivativeInstrumentLiabilitiesAtFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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_DerivativeInstrumentsGainLossLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_DerivativeInstrumentsGainLossByHedgingRelationshipAxis=us-gaap_CashFlowHedgingMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_HedgingDesignationAxis=us-gaap_DesignatedAsHedgingInstrumentMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateContractMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateSwapMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |