Special Purpose Entities, Including Variable Interest Entities - Summary of Fair Value of Fixed Income Securities, by Asset-Type, Held by Consolidated Variable Interest Entities (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Mar. 31, 2025	Dec. 31, 2024
Variable Interest Entities [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	$ 289,712	$ 266,292
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	260	881
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	$ 5,351	$ 3,994	$ 5,351