v3.26.1
Shareholders' Equity (Details) - USD ($)
$ in Thousands
 3 Months Ended
May 03, 2024
Mar. 31, 2026
Dec. 31, 2025
Class of Stock [Line Items]      
Total capitalization   $ 2,970,956 $ 2,825,326
Otter Tail Power Company      
Class of Stock [Line Items]      
Equity to total capitalization ratio   51.60%  
Net assets restricted from distribution   $ 991,000  
Minimum | Otter Tail Power Company | Minnesota Public Utilities Commission      
Class of Stock [Line Items]      
Public utilities, requested equity capital structure (as a percent)   46.70%  
Maximum | Otter Tail Power Company      
Class of Stock [Line Items]      
Total capitalization   $ 2,400,000  
Maximum | Otter Tail Power Company | Minnesota Public Utilities Commission      
Class of Stock [Line Items]      
Public utilities, requested equity capital structure (as a percent)   57.10%  
Second Shelf Registration      
Class of Stock [Line Items]      
Shelf registration (in shares) 1,500,000    
Number of shares issued (in shares)   24,500  
Number of shares available for grant (in shares)   1,306,321