v3.26.1
Related Party Transactions - BGC Credit Agreement (Details) - Related Party - USD ($)
3 Months Ended 6 Months Ended 12 Months Ended
Jan. 09, 2026
Nov. 12, 2025
Jun. 30, 2025
Jun. 05, 2025
Apr. 14, 2025
Apr. 04, 2025
Jun. 07, 2024
Mar. 08, 2024
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Dec. 31, 2025
Aug. 06, 2018
Mar. 19, 2018
Related Party Transaction [Line Items]                              
Interest income                 $ 3,500,000 $ 4,300,000 $ 6,700,000 $ 8,000,000.0      
Revolving credit facility | BGC Credit Agreement                              
Related Party Transaction [Line Items]                              
Principal amount of debt component             $ 400,000,000.0 $ 400,000,000.0           $ 400,000,000.0 $ 250,000,000.0
Basis points (less than)               0.25%              
Average interest rate (as a percent)               1.00%     5.36%   5.45%    
Debt instrument, extended term (in years)               1 year              
Debt instrument, non-extension notice term               6 months              
Maturity term maximum             35 days                
Proceeds from borrowings   $ 20,000,000.0                     $ 20,000,000.0    
Repayment of outstanding borrowings $ 20,000,000.0                            
Line of credit facility, outstanding amount                 0   $ 0        
Interest expense recorded                 0 0 0 0      
Revolving credit facility | BGC Credit Agreement | Cantor                              
Related Party Transaction [Line Items]                              
Average interest rate (as a percent)                         6.17%    
Proceeds from borrowings           $ 120,000,000.0                  
Repayment of outstanding borrowings     $ 77,000,000.0 $ 28,000,000.0 $ 15,000,000.0                    
Line of credit facility, outstanding amount                 0   0   $ 0    
Interest income                 $ 0 $ 1,500,000 $ 0 $ 1,500,000