v3.26.1
Equity and Noncontrolling Interest - Additional Information (Details)
3 Months Ended
Feb. 18, 2026
USD ($)
$ / shares
shares
Aug. 31, 2025
Mar. 31, 2026
USD ($)
$ / shares
shares
Dec. 31, 2025
USD ($)
$ / shares
shares
Feb. 28, 2026
$ / shares
Class of Stock [Line Items]          
Preferred stock, shares authorized     10,000,000 10,000,000  
Preferred stock, par value | $ / shares     $ 0.0001 $ 0.0001  
Preferred stock, shares issued     0 0  
Preferred stock, shares outstanding     0 0  
Description of redemption     Cardinal’s ("OpCo's") amended and restated operating agreement provides that the Continuing Equity Holders have the right (the “Redemption Right”) to cause OpCo to redeem all or a portion of their Class B LLC units, together with a corresponding number of shares of Class B Common Stock, for newly issued shares of Cardinal Infrastructure Group Inc.'s Class A Common Stock on a one-for-one basis (subject to customary adjustments for stock splits, stock dividends, and reclassifications). Alternatively, Cardinal Infrastructure Group Inc. may, at its option (the “Call Right”), elect to directly acquire the tendered LLC units and Class B Common Stock from the Continuing Equity Holder in exchange for Class A Common Stock on the same one-for-one basis.    
Gain or loss on exchange of equity transaction | $     $ 0    
Gain or loss recognized | $       $ 0  
OpCo          
Class of Stock [Line Items]          
Percentage of voting rights     100.00%    
OpCo | AL Grading Contractors LLC          
Class of Stock [Line Items]          
Common unit, issued 4,186,062        
OpCo | AL Grading Contractors LLC | 2025 Plan          
Class of Stock [Line Items]          
Business combination, equity interest, share issued     345,666    
Cardinal NC | Aviator Paving Company LLC          
Class of Stock [Line Items]          
Ownership interests in subsidiary   60.00%      
Cardinal NC | Cardinal Civil Contracting NC LLC          
Class of Stock [Line Items]          
Ownership interests in subsidiary   70.00%      
Cardinal NC | Civil Drilling & Blasting, LLC          
Class of Stock [Line Items]          
Ownership interests in subsidiary   90.00%      
Cardinal NC | Cardinal Civil Contracting Charlotte, LLC          
Class of Stock [Line Items]          
Ownership interests in subsidiary   75.00%      
Cardinal NC | Cardinal Civil Contracting Triad, LLC          
Class of Stock [Line Items]          
Ownership interests in subsidiary   80.00%      
Cardinal NC | Civil Underground and Boring Company, LLC          
Class of Stock [Line Items]          
Ownership interests in subsidiary   70.00%      
Class A Common Stock          
Class of Stock [Line Items]          
Common stock, shares authorized     500,000,000 500,000,000  
Common stock, par value per share | $ / shares     $ 0.0001 $ 0.0001  
Common stock voting rights     Each share of Class A Common Stock entitles its holder to one vote per share on all matters presented to Cardinal Infrastructure Group Inc.’s stockholders.    
Common stock, shares issued     15,292,984 14,947,318  
Common stock, shares outstanding     15,292,984 14,947,318  
Class A Common Stock | AL Grading Contractors LLC | 2025 Plan          
Class of Stock [Line Items]          
Common stock, par value per share | $ / shares $ 0.0001        
Closing share price | $ / shares $ 24.56        
Business combination, equity interest, share issued 345,666        
Class A Common Stock | OpCo | AL Grading Contractors LLC          
Class of Stock [Line Items]          
Closing share price | $ / shares         $ 24.56
Consideration transferred in business combination | $ $ 102,809,683        
Class A Common Stock | OpCo | Continuing Equity Holders          
Class of Stock [Line Items]          
Stock split ratio     1    
Class A Common Stock | OpCo | Cardinal Infrastructure Group Inc.          
Class of Stock [Line Items]          
Stock split ratio     1    
Class B Common Stock          
Class of Stock [Line Items]          
Common stock, shares authorized     500,000,000 500,000,000  
Common stock, par value per share | $ / shares     $ 0.0001 $ 0.0001  
Common stock voting rights     Each share of Class B Common Stock entitles its holder to one vote per share on all matters presented to Cardinal Infrastructure Group Inc.’s stockholders.    
Common stock, shares issued     27,573,875 23,387,813  
Common stock, shares outstanding     27,573,875 23,387,813  
Class B Common Stock | OpCo | AL Grading Contractors LLC          
Class of Stock [Line Items]          
Common stock, par value per share | $ / shares $ 0.0001