XML 60 R47.htm IDEA: XBRL DOCUMENT v3.25.3
Investments - Summary of Gross Unrealized Losses and Fair Values of Ambac's Available-for-Sale Investments (Details)
$ in Thousands
Sep. 30, 2025
USD ($)
Dec. 31, 2024
USD ($)
Debt Securities, Available-for-sale [Line Items]    
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months $ 7,750 $ 51,012
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss 71 792
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer 53,832 68,012
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss 2,616 4,559
Debt Securities, Available-for-sale, Unrealized Loss Position 61,582 119,024
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax 2,687 5,351
DebtSecuritiesAvailableForSaleContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss, including pledged securities 71  
Debt Securities , Available for sale, Continuous Unrealized Loss Position, 7,750 51,012
Debt Securities, Available for sale, Unrealized Loss Position, Including Pledged Securities   119,024
Short-term Investments [Member]    
Debt Securities, Available-for-sale [Line Items]    
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months 0 0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss 0 0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer 0 0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss 0 0
Debt Securities, Available-for-sale, Unrealized Loss Position 0 0
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax 0 0
Fixed Income Investments And Other Investments [Member]    
Debt Securities, Available-for-sale [Line Items]    
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax 2,687  
Fixed Income Securities [Member]    
Debt Securities, Available-for-sale [Line Items]    
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months 7,750 51,012
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss 71 792
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer 53,832 68,012
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss 2,616 4,559
Debt Securities, Available-for-sale, Unrealized Loss Position 61,582 119,024
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax 2,687 5,351
Fixed Income Securities [Member] | Municipal Bonds [Member]    
Debt Securities, Available-for-sale [Line Items]    
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months 318 6,042
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss 15 112
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer 6,191 6,582
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss 264 458
Debt Securities, Available-for-sale, Unrealized Loss Position 6,509 12,624
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax 279 570
Fixed Income Securities [Member] | Corporate Debt Securities [Member]    
Debt Securities, Available-for-sale [Line Items]    
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months 3,269 23,784
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss 13 269
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer 32,855 46,612
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss 2,167 3,636
Debt Securities, Available-for-sale, Unrealized Loss Position 36,124 70,396
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax $ 2,180 3,905
Debt Securities, Available-for-Sale, Unrealized Loss Position, Number of Positions 99,000  
Fixed Income Securities [Member] | US Government Debt Securities [Member]    
Debt Securities, Available-for-sale [Line Items]    
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months $ 3,012 15,919
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss 34 344
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer 13,064 14,818
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss 171 465
Debt Securities, Available-for-sale, Unrealized Loss Position 16,076 30,737
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax 205 809
Fixed Income Securities [Member] | Residential Mortgage-Backed Securities [Member]    
Debt Securities, Available-for-sale [Line Items]    
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months 0 2,446
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss 0 29
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer 1,722 0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss 14 0
Debt Securities, Available-for-sale, Unrealized Loss Position 1,722 2,446
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax 14 29
Fixed Income Securities [Member] | Commercial Mortgage Backed Securities [Member]    
Debt Securities, Available-for-sale [Line Items]    
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months 761 738
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss 9 34
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer 0 0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss 0 0
Debt Securities, Available-for-sale, Unrealized Loss Position 761 738
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax 9 34
Fixed Income Securities [Member] | Collateralized Debt Obligations [Member]    
Debt Securities, Available-for-sale [Line Items]    
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months 390 655
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss 0 2
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer 0 0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss 0 0
Debt Securities, Available-for-sale, Unrealized Loss Position 390 655
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax 0 2
Fixed Income Securities [Member] | Asset-backed Securities [Member]    
Debt Securities, Available-for-sale [Line Items]    
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months 0 1,428
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss 0 2
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer 0 0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss 0 0
Debt Securities, Available-for-sale, Unrealized Loss Position 0 1,428
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax $ 0 $ 2