XML 119 R104.htm IDEA: XBRL DOCUMENT v3.21.1

Financial Guarantees (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Financial Guarantees [Line Items]
Term of standby letters of credit, years	1 year
Notional amount of standby letters of credit	$ 75,100,000	$ 86,900,000
Carrying value of letters of credit	500,000	$ 500,000
Interest Rate Swap
Financial Guarantees [Line Items]
Notional amount	$ 68,200,000

X

- Definition

Carrying value of standby letters of credit financial instruments.

+ References

No definition available.

+ Details

Name:	onb_CarryingValueOfLetterOfCredit
Namespace Prefix:	onb_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Financial guarantees.

+ References

No definition available.

+ Details

Name:	onb_FinancialGuaranteesLineItems
Namespace Prefix:	onb_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Amount of agreement to extend credit in the form of a standby letter of credit.

+ References

No definition available.

+ Details

Name:	onb_NotionalAmountOfStandbyLettersOfCredit
Namespace Prefix:	onb_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Length of time that standby letters of credit are effective.

+ References

No definition available.

+ Details

Name:	onb_TermOfStandbyLettersOfCredit
Namespace Prefix:	onb_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Nominal or face amount used to calculate payment on derivative.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5580258-113959

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5579245-113959

+ Details

Name:	us-gaap_DerivativeNotionalAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant

X

- Details

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