Fair value measurements - Schedule of Investments in Company-Sponsored Funds (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	$ 10,543,000	$ 5,555
Unfunded Commitments	741	741
Private equity funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value	10,543,000	5,555
Unfunded Commitments	$ 741	$ 741