XML 14 R54.htm IDEA: XBRL DOCUMENT v2.4.1.9
Loans And Allowance For Credit Losses (Summary Of Net Financial Impact On Interest Income Due To Interest Rate Modifications Below Market For Accruing TDR Loans) (Details) (USD $)
In Thousands, unless otherwise specified
 3 Months Ended 9 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Sep. 30, 2012
Sep. 30, 2011
Dec. 31, 2014
Financing Receivable, Modifications [Line Items]          
Financing Receivable, Modifications, Subsequent Default, Recorded Investment $ 2,424us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1 $ 327us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1 $ 74,500us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1 $ 142,400us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1  
Loans and Leases Receivable, Gross, Consumer, Home Equity 2,314,806us-gaap_LoansAndLeasesReceivableConsumerHomeEquity       2,321,150us-gaap_LoansAndLeasesReceivableConsumerHomeEquity
Net financial impact on interest income 594zion_DecreaseInInterestIncomeDueToInterestRateChangesForAccruingTroubledDebtRestructuringsLoans 639zion_DecreaseInInterestIncomeDueToInterestRateChangesForAccruingTroubledDebtRestructuringsLoans      
Commercial [Member]          
Financing Receivable, Modifications [Line Items]          
Net financial impact on interest income 169zion_DecreaseInInterestIncomeDueToInterestRateChangesForAccruingTroubledDebtRestructuringsLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_CommercialPortfolioSegmentMember		 124zion_DecreaseInInterestIncomeDueToInterestRateChangesForAccruingTroubledDebtRestructuringsLoans
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= us-gaap_CommercialPortfolioSegmentMember		      
Commercial Real Estate [Member]          
Financing Receivable, Modifications [Line Items]          
Net financial impact on interest income 146zion_DecreaseInInterestIncomeDueToInterestRateChangesForAccruingTroubledDebtRestructuringsLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
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Consumer Portfolio Segment [Member]          
Financing Receivable, Modifications [Line Items]          
Loans and Leases Receivable, Gross, Consumer, Home Equity 2,314,806us-gaap_LoansAndLeasesReceivableConsumerHomeEquity
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
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Net financial impact on interest income 279zion_DecreaseInInterestIncomeDueToInterestRateChangesForAccruingTroubledDebtRestructuringsLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= us-gaap_ConsumerPortfolioSegmentMember		 311zion_DecreaseInInterestIncomeDueToInterestRateChangesForAccruingTroubledDebtRestructuringsLoans
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Commercial And Industrial [Member]          
Financing Receivable, Modifications [Line Items]          
Financing Receivable, Modifications, Subsequent Default, Recorded Investment 44us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1
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Net financial impact on interest income (57)zion_DecreaseInInterestIncomeDueToInterestRateChangesForAccruingTroubledDebtRestructuringsLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
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Owner Occupied [Member]          
Financing Receivable, Modifications [Line Items]          
Financing Receivable, Modifications, Subsequent Default, Recorded Investment 986us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1
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Net financial impact on interest income (112)zion_DecreaseInInterestIncomeDueToInterestRateChangesForAccruingTroubledDebtRestructuringsLoans
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Commercial Loan [Member]          
Financing Receivable, Modifications [Line Items]          
Financing Receivable, Modifications, Subsequent Default, Recorded Investment 1,030us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1
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Commercial Real Estate Construction Financing Receivable [Member]          
Financing Receivable, Modifications [Line Items]          
Financing Receivable, Modifications, Subsequent Default, Recorded Investment 1,284us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1
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Net financial impact on interest income (37)zion_DecreaseInInterestIncomeDueToInterestRateChangesForAccruingTroubledDebtRestructuringsLoans
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Term [Member]          
Financing Receivable, Modifications [Line Items]          
Financing Receivable, Modifications, Subsequent Default, Recorded Investment 0us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1
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Net financial impact on interest income (109)zion_DecreaseInInterestIncomeDueToInterestRateChangesForAccruingTroubledDebtRestructuringsLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
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Home Equity Credit Line [Member]          
Financing Receivable, Modifications [Line Items]          
Net financial impact on interest income (1)zion_DecreaseInInterestIncomeDueToInterestRateChangesForAccruingTroubledDebtRestructuringsLoans
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One Through Four Family Residential [Member]          
Financing Receivable, Modifications [Line Items]          
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Net financial impact on interest income (271)zion_DecreaseInInterestIncomeDueToInterestRateChangesForAccruingTroubledDebtRestructuringsLoans
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
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Construction And Other Consumer Real Estate [Member]          
Financing Receivable, Modifications [Line Items]          
Financing Receivable, Modifications, Subsequent Default, Recorded Investment 0us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1
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Net financial impact on interest income (7)zion_DecreaseInInterestIncomeDueToInterestRateChangesForAccruingTroubledDebtRestructuringsLoans
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Commercial Real Estate [Member]          
Financing Receivable, Modifications [Line Items]          
Financing Receivable, Modifications, Subsequent Default, Recorded Investment 1,284us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1
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Home Equity Line of Credit [Member]          
Financing Receivable, Modifications [Line Items]          
Financing Receivable, Modifications, Subsequent Default, Recorded Investment 0us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1
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Consumer Loan [Member]          
Financing Receivable, Modifications [Line Items]          
Financing Receivable, Modifications, Subsequent Default, Recorded Investment 110us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1
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Nonaccruing [Member]          
Financing Receivable, Modifications [Line Items]          
Financing Receivable, Modifications, Subsequent Default, Recorded Investment 2,314us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1
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Nonaccruing [Member] | Commercial And Industrial [Member]          
Financing Receivable, Modifications [Line Items]          
Financing Receivable, Modifications, Subsequent Default, Recorded Investment 44us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1
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Nonaccruing [Member] | Owner Occupied [Member]          
Financing Receivable, Modifications [Line Items]          
Financing Receivable, Modifications, Subsequent Default, Recorded Investment 986us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1
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Financing Receivable, Modifications [Line Items]          
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Financing Receivable, Modifications [Line Items]          
Financing Receivable, Modifications, Subsequent Default, Recorded Investment 1,284us-gaap_FinancingReceivableModificationsSubsequentDefaultRecordedInvestment1
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Financing Receivable, Modifications [Line Items]          
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Financing Receivable, Modifications [Line Items]          
Loans and Leases Receivable, Gross, Consumer, Home Equity         1,022us-gaap_LoansAndLeasesReceivableConsumerHomeEquity
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Financing Receivable, Modifications [Line Items]          
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Financing Receivable, Modifications [Line Items]          
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Accruing [Member] | Commercial Loan [Member]          
Financing Receivable, Modifications [Line Items]          
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Accruing [Member] | Term [Member]          
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Financing Receivable, Modifications [Line Items]          
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Accruing [Member] | Home Equity Line of Credit [Member]          
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[1] Includes TDRs that resulted from other modification types including, but not limited to, a legal judgment awarded on different terms, a bankruptcy plan confirmed on different terms, a settlement that includes the delivery of collateral in exchange for debt reduction, etc.
[2] Includes TDRs that resulted from a combination of any of the previous modification types.