Investments - Schedule of Investments in Two Sigma Funds (Details) - USD ($) $ in Thousands	Jun. 30, 2026	Dec. 31, 2025
Marketable Securities [Line Items]
Cost	$ 1,574,091	$ 1,355,563
Net Unrealized Gains (Losses)	270,067	232,095
Investments in Two Sigma Funds, at fair value	1,844,158	1,587,658
Two Sigma Spectrum Portfolio, LLC
Marketable Securities [Line Items]
Cost	43,863	500,616
Net Unrealized Gains (Losses)	9,324	131,996
Investments in Two Sigma Funds, at fair value	53,187	632,612
Two Sigma Equity Spectrum Portfolio, LLC
Marketable Securities [Line Items]
Cost	915,005	187,718
Net Unrealized Gains (Losses)	170,510	49,906
Investments in Two Sigma Funds, at fair value	1,085,515	237,624
Two Sigma Absolute Return Portfolio, LLC
Marketable Securities [Line Items]
Cost	10,784	93,092
Net Unrealized Gains (Losses)	1,417	8,882
Investments in Two Sigma Funds, at fair value	12,201	101,974
Two Sigma Futures Portfolio, LLC
Marketable Securities [Line Items]
Cost	196,068	192,064
Net Unrealized Gains (Losses)	75,667	44,998
Investments in Two Sigma Funds, at fair value	271,735	237,062
Two Sigma Horizon Portfolio, LLC
Marketable Securities [Line Items]
Cost	252,942	241,090
Net Unrealized Gains (Losses)	15,344	4,585
Investments in Two Sigma Funds, at fair value	268,286	245,675
Two Sigma Navigator Portfolio, LLC
Marketable Securities [Line Items]
Cost	132,908	110,577
Net Unrealized Gains (Losses)	(1,545)	(9,585)
Investments in Two Sigma Funds, at fair value	131,363	100,992
Two Sigma Kuiper Portfolio, LLC
Marketable Securities [Line Items]
Cost	22,521	30,406
Net Unrealized Gains (Losses)	(650)	1,313
Investments in Two Sigma Funds, at fair value	$ 21,871	$ 31,719