v3.25.2
General - Narrative (Details) - USD ($)
 3 Months Ended 6 Months Ended
Jun. 30, 2025
Mar. 31, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
Dec. 31, 2024
Organization, Consolidation and Presentation of Financial Statements [Line Items]            
Potentially dilutive securities (in shares) 0   0 0 0  
Dividends declared and paid (in dollars per share) $ 0.3175   $ 0.3175 $ 0.6350 $ 0.6350  
Policy acquisition costs $ 227,880,000   $ 203,682,000 $ 456,601,000 $ 399,722,000  
Advertising expenses 7,400,000   3,900,000 12,900,000 7,200,000  
Gain (loss) on sale of fixed assets       2,691,000 (71,000)  
Ceded premiums earned 54,400,000   31,400,000 161,100,000 62,500,000  
Losses and loss adjustment expenses, ceded 400,000   (100,000) 1,292,900,000 (900,000)  
Revenue from contract with customer 6,800,000   6,000,000.0 13,900,000 11,700,000  
Cost of goods and services sold 3,600,000   3,200,000 7,200,000 6,400,000  
Contract with customer, asset 0     0   $ 0
Contract with customer, liability 0     0   0
Revenue, remaining performance obligation 0     0   $ 0
Accrued interest receivable considered uncollectible or written off       0 0  
Reinsurance Contract [Axis]: 100% Reinsurance Limit Used            
Organization, Consolidation and Presentation of Financial Statements [Line Items]            
Ceded premiums earned 0 $ 52,000,000   52,000,000    
Reinsurance Contract [Axis]: Catastrophe Participation Reinsurance Contract (the "Contract")            
Organization, Consolidation and Presentation of Financial Statements [Line Items]            
Reinsurance reimbursable amount 30,000,000     $ 30,000,000    
Reinsurance retention policy, threshold loss ratio       73.50%    
Reinsurance Contract [Axis]: Catastrophe Reinsurance Treaty (the "Treaty")            
Organization, Consolidation and Presentation of Financial Statements [Line Items]            
Reinsurance retention policy, excess retention, amount reinsured       $ 2,140,000,000    
Reinsurance policy, amount retained       200,000,000    
Reinsurance Contract [Axis]: Pro-Forma, $0 Reinsurance Limit            
Organization, Consolidation and Presentation of Financial Statements [Line Items]            
Ceded premiums earned 26,000,000 $ 26,000,000   52,000,000    
Reinsurance Contract [Axis]: Property Quota Share Reinsurance Contract ("Quota Share")            
Organization, Consolidation and Presentation of Financial Statements [Line Items]            
Assumed maximum possible loss 32,000,000     32,000,000    
Assumed premium written       11,000,000    
Folsom, California Office Building | Disposal Group, Held-for-sale, Not Discontinued Operations            
Organization, Consolidation and Presentation of Financial Statements [Line Items]            
Gain (loss) as a result of the held-for-sale classification     $ (5,400,000)   $ (5,400,000)  
Folsom, California Office Building | Disposal Group, Disposed of by Sale, Not Discontinued Operations            
Organization, Consolidation and Presentation of Financial Statements [Line Items]            
Sale price of fixed asset 13,000,000.0     13,000,000.0    
Gain (loss) on sale of fixed assets $ 2,700,000     $ 2,700,000