Insurance Contracts - Summary of Information Related to Policies Currently Included in Ambac's Loss Reserves or Subrogation Recoverable (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Mar. 31, 2024
Financial Guarantee Insurance Contracts, Claim Liability [Line Items]
Ceded Loss And Loss Expenses Paid Not Yet Recovered		$ 15,088
Financial Guarantee
Financial Guarantee Insurance Contracts, Claim Liability [Line Items]
Ceded Loss And Loss Expenses Paid Not Yet Recovered	$ 56,190