XML 16 R1.htm IDEA: XBRL DOCUMENT v3.22.0.1
Cover - USD ($)
shares in Thousands
 12 Months Ended
Dec. 31, 2021
Jan. 31, 2022
Jun. 30, 2021
Cover [Abstract]      
Document Type 10-K    
Document Annual Report true    
Document Period End Date Dec. 31, 2021    
Current Fiscal Year End Date --12-31    
Document Transition Report false    
Entity File Number 1-15817    
Entity Registrant Name OLD NATIONAL BANCORP    
Entity Incorporation, State or Country Code IN    
Entity Tax Identification Number 35-1539838    
Entity Address, Address Line One One Main Street    
Entity Address, City or Town Evansville,    
Entity Address, State or Province IN    
Entity Address, Postal Zip Code 47708    
City Area Code 800    
Local Phone Number 731-2265    
Title of 12(b) Security Common Stock, No Par Value    
Trading Symbol ONB    
Security Exchange Name NASDAQ    
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Filer Category Large Accelerated Filer    
Entity Small Business false    
Entity Emerging Growth Company false    
ICFR Auditor Attestation Flag true    
Entity Shell Company false    
Entity Public Float     $ 2,884,796,345
Entity Common Stock, Shares Outstanding (in shares)   165,845  
Documents Incorporated by Reference Portions of the Proxy Statement for the 2022 Annual Meeting of Shareholders are incorporated by reference into Part III of this Form 10-K.    
Amendment Flag false    
Document Fiscal Year Focus 2021    
Document Fiscal Period Focus FY    
Entity Central Index Key 0000707179