v3.26.1
Rates and Other Regulatory Activities - Additional Information (Detail)
$ in Thousands
 3 Months Ended
Mar. 31, 2026
USD ($)
Dekatherm
Mar. 31, 2025
Dec. 31, 2026
USD ($)
Dec. 31, 2025
USD ($)
Rates and Other Regulatory Activities [Line Items]        
Regulatory Liabilities $ (83,100)     $ 83,400
Gas Utility Access and Replacement Directive Related Capital Expenditures 205,000      
Base Rate Increase 46,900      
RSAM     $ 25,000  
Safety, Access, and Facility Enhancement Capital Expenditures 50,000      
Total Projected Capital Expenditures 255,000      
Safety, Access, and Facility Enhancement Capital Expenditures $ 205,000      
Number of Miles of Distribution Mains 150 160    
Environmental liabilities $ 3,000     2,900
FCG Depr Reserve Imbalance 6,800      
FCG Interim Rate Relief 16,200      
FCG SAFE Revs $ 16,400      
FCG Rate Case Percent 11.25%      
Eastern Shore Gas Company [Member]        
Rates and Other Regulatory Activities [Line Items]        
Number of Miles of Distribution Mains   5.5    
Maryland Natural Gas [Member]        
Rates and Other Regulatory Activities [Line Items]        
Permanent Rates $ 6,900      
Annual Rate Case Recovery $ 2,600      
Rate Case ROE 11.50%      
Total Rate Case Recovery $ 3,500      
Incremental Rate Case Recovery 900      
Florida City Gas        
Rates and Other Regulatory Activities [Line Items]        
Total Base Rate Increase     23,300  
Base Rate Increase - liquefied natural gas facility     3,800  
Base Rate Increase Base - SAFE investments transfer to base rates     5,300  
Base Rate Increase     14,100  
Florida City Gas | Storm Reserve        
Rates and Other Regulatory Activities [Line Items]        
Regulatory Liabilities     800  
Florida Electric Distribution        
Rates and Other Regulatory Activities [Line Items]        
Permanent Rates 8,600      
Annual Rate Case Recovery $ 1,800      
Rate Case ROE 11.30%      
Proprosed Rates $ 12,600      
Deferred Annual Rate Case Recovery 1,000      
Step Up Rate Case Recovery 700      
Delaware natural gas division [Member]        
Rates and Other Regulatory Activities [Line Items]        
Interim Rates 2,500      
Permanent Rates 12,100      
Annual Rate Case Recovery $ 6,100      
Rate Case ROE 11.50%      
Florida Public Utilities Company [Member]        
Rates and Other Regulatory Activities [Line Items]        
Environmental liabilities $ 3,300     $ 3,100
Eastern Shore Gas Company [Member]        
Rates and Other Regulatory Activities [Line Items]        
Regulatory Liabilities $ 34,200      
Newberry Expansion | Peninsula Pipeline Company [Member]        
Rates and Other Regulatory Activities [Line Items]        
Additional Firm Natural Gas Transportation Deliverability | Dekatherm 8,000      
East Coast Reinforcement Projects: Boynton Beach | Peninsula Pipeline Company [Member]        
Rates and Other Regulatory Activities [Line Items]        
Additional Firm Natural Gas Transportation Deliverability | Dekatherm 15,000      
East Coast Reinforcement Projects: New Smyrna Beach | Peninsula Pipeline Company [Member]        
Rates and Other Regulatory Activities [Line Items]        
Additional Firm Natural Gas Transportation Deliverability | Dekatherm 3,400      
Central Florida Reinforcement Projects | Peninsula Pipeline Company [Member]        
Rates and Other Regulatory Activities [Line Items]        
Additional Firm Natural Gas Transportation Deliverability | Dekatherm 8,700      
Central Florida Reinforcement Projects: Plant City | Peninsula Pipeline Company [Member]        
Rates and Other Regulatory Activities [Line Items]        
Additional Firm Natural Gas Transportation Deliverability | Dekatherm 5,000      
St. Cloud Project Amendment | Peninsula Pipeline Company [Member]        
Rates and Other Regulatory Activities [Line Items]        
Additional Firm Natural Gas Transportation Deliverability | Dekatherm 10,000      
FL Mandatory Relocates | Florida City Gas        
Rates and Other Regulatory Activities [Line Items]        
Projected Revenue $ 1,000      
FL Mandatory Relocates | Florida Natural Gas Distribution        
Rates and Other Regulatory Activities [Line Items]        
Projected Revenue $ 500      
Storm Protection Plan | Florida Electric Distribution        
Rates and Other Regulatory Activities [Line Items]        
Cost Recovery Storm Protection Plan     $ 20,400