XML 78 R61.htm IDEA: XBRL DOCUMENT
v3.25.0.1

Basis of Presentation and Significant Accounting Policies - Additional Information (Details) - USD ($) $ in Thousands |  |  | 1 Months Ended | 12 Months Ended
--- | --- | --- | --- | ---
Feb. 28, 2022 | Feb. 15, 2022 | Apr. 30, 2024 | Dec. 31, 2024 | Dec. 31, 2023 | Dec. 31, 2022
Property, Plant and Equipment [Line Items] |  |  |  |  |  |
FDIC assessment |  |  |  | $ 44,681 | $ 56,730 | $ 19,332
Issuance of common stock |  |  |  | 417,598 |  | 2,446,312
Series A Preferred Stock |  |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |  |
Shares issued for acquisition (in shares) |  | 108,000 |  |  |  |
Series C Preferred Stock |  |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |  |
Shares issued for acquisition (in shares) |  | 122,500 |  |  |  |
Preferred Stock |  |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |  |
Issuance of common stock | $ 243,700 |  |  |  |  |
First Midwest |  |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |  |
Shares issued for acquisition (in shares) | 129,400,000 |  |  |  |  |
Issuance of common stock | $ 2,400,000 |  |  |  |  |
CapStar Financial Holdings, Inc. |  |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |  |
Shares issued for acquisition (in shares) |  |  | 24,000,000 |  |  |
Issuance of common stock |  |  | $ 417,600 |  |  |
Old National Bancorp |  |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |  |
Estimated uninsured deposits |  |  |  |  |  | $ 12,000,000
FDIC assessment |  |  |  | $ 3,000 | $ 19,100 |
Minimum |  |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |  |
Maturity of short-term securities sold under agreements to repurchase |  |  |  | 1 day |  |
Minimum | Core Deposits and Other Intangible Assets |  |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |  |
Estimated useful lives of core deposits and customer relationships |  |  |  | 5 years |  |
Minimum | Building and Building Improvements |  |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |  |
Useful lives for premises and equipment, years |  |  |  | 10 years |  |
Minimum | Furniture and Equipment |  |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |  |
Useful lives for premises and equipment, years |  |  |  | 3 years |  |
Maximum |  |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |  |
Maturity of short-term securities sold under agreements to repurchase |  |  |  | 4 days |  |
Maximum | Core Deposits and Other Intangible Assets |  |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |  |
Estimated useful lives of core deposits and customer relationships |  |  |  | 15 years |  |
Maximum | Building and Building Improvements |  |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |  |
Useful lives for premises and equipment, years |  |  |  | 39 years |  |
Maximum | Furniture and Equipment |  |  |  |  |  |
Property, Plant and Equipment [Line Items] |  |  |  |  |  |
Useful lives for premises and equipment, years |  |  |  | 7 years |  |

X
- Definition Number of days from transaction date that securities sold under agreement to repurchase mature. + References No definition available. + Details
Name: | onb_MaturityOfSecuritiesSoldUnderAgreementToRepurchase
Namespace Prefix: | onb_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of uninsured deposit liability. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Name Regulation S-K (SK) -Number 229 -Section 1406 -Paragraph e -Publisher SEC + Details
Name: | us-gaap_DepositLiabilityUninsured
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of expense for Federal Deposit Insurance Corporation (FDIC) insurance. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 942 -SubTopic 220 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04(14)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478524/942-220-S99-1 + Details
Name: | us-gaap_FederalDepositInsuranceCorporationPremiumExpense
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
Name: | us-gaap_FiniteLivedIntangibleAssetUsefulLife
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
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 Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 842 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 7A -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org/1943274/2147478964/842-20-50-7A + Details
Name: | us-gaap_PropertyPlantAndEquipmentLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment. + References No definition available. + Details
Name: | us-gaap_PropertyPlantAndEquipmentUsefulLife
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of shares of stock issued during the period pursuant to acquisitions. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(28)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 505 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480008/505-10-S99-1 + Details
Name: | us-gaap_StockIssuedDuringPeriodSharesAcquisitions
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Value of stock issued pursuant to acquisitions during the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 50 -Paragraph 2 -SubTopic 10 -Topic 505 -Publisher FASB -URI https://asc.fasb.org/1943274/2147481112/505-10-50-2 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(30)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(31)) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1 Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 505 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -Publisher FASB -URI https://asc.fasb.org/1943274/2147480008/505-10-S99-1 + Details
Name: | us-gaap_StockIssuedDuringPeriodValueAcquisitions
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=us-gaap_SeriesAPreferredStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=us-gaap_SeriesCPreferredStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=us-gaap_PreferredStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=onb_FirstMidwestMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=onb_CapStarFinancialHoldingsIncMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ConsolidatedEntitiesAxis=srt_ParentCompanyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=onb_CoreDepositsAndOtherIntangibleAssetsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_BuildingAndBuildingImprovementsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_FurnitureAndFixturesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |