v3.26.3
Fair value of assets and liabilities - Expected Timing Sensitivity of Level 3 Valuations (Details) - USD ($)
$ in Thousands
 6 Months Ended 9 Months Ended
Jun. 30, 2026
Sep. 30, 2026
Dec. 31, 2025
6 months duration      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Increase in expected timing of a favorable outcome 6 months 6 months  
Decrease in expected timing of a favorable outcome 6 months 6 months  
Decrease in consolidated income and net assets due to increase in expected timing of a favorable outcome   $ (142,903) $ (229,491)
Increase in consolidated income and net assets due to decrease in expected timing of a favorable outcome   $ 162,524 199,038
12 months duration      
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]      
Increase in expected timing of a favorable outcome 12 months 12 months  
Decrease in expected timing of a favorable outcome 12 months 12 months  
Decrease in consolidated income and net assets due to increase in expected timing of a favorable outcome   $ (291,304) (422,303)
Increase in consolidated income and net assets due to decrease in expected timing of a favorable outcome   $ 312,624 $ 383,172