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Cover - USD ($)
 12 Months Ended
Dec. 31, 2023
Jan. 31, 2024
Jun. 30, 2023
Cover [Abstract]      
Document Type 10-K    
Document Annual Report true    
Document Period End Date Dec. 31, 2023    
Current Fiscal Year End Date --12-31    
Document Transition Report false    
Entity File Number 0-53713    
Entity Registrant Name OTTER TAIL CORPORATION    
Entity Incorporation, State or Country Code MN    
Entity Tax Identification Number 27-0383995    
Entity Address, Address Line One 215 South Cascade Street    
Entity Address, Address Line Two Box 496    
Entity Address, City or Town Fergus Falls    
Entity Address, State or Province MN    
Entity Address, Postal Zip Code 56538-0496    
City Area Code 866    
Local Phone Number 410-8780    
Title of 12(b) Security Common Shares, par value $5.00 per share    
Trading Symbol OTTR    
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    
Document Financial Statement Error Correction false    
Entity Shell Company false    
Entity Public Float     $ 3,646,181,401
Entity Common Stock, Shares Outstanding   41,710,521  
Documents Incorporated by Reference
The Registrant's definitive Proxy Statement for its 2024 Annual Meeting of Shareholders is incorporated by reference into Part III of this Form 10-K.
    
Entity Central Index Key 0001466593    
Amendment Flag false    
Document Fiscal Period Focus FY    
Document Fiscal Year Focus 2023