Financial Guarantee Insurance Contracts - Summary of Information Related to Policies Currently Included in Ambac's Loss Reserves or Subrogation Recoverable (Detail) - USD ($) $ in Thousands	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Less:
Ceded Loss And Loss Expenses Paid Not Yet Recovered		$ 8,765	$ 1,397
Financial Guarantee
Less:
Ceded Loss And Loss Expenses Paid Not Yet Recovered	$ 36,210