Consolidated Statements of Total Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Net investment income:
Interest Income, Debt Securities, Available-for-Sale, Operating	$ 2,894	$ 3,670
Net investment income	2,815	3,640
Realized Investment Gains (Losses)	(3)	1
Change in fair value of credit derivatives:
Derivative, Gain (Loss) on Derivative, Net	427	(48)
Insurance Commissions and Fees	36,771	17,729
Other Operating Income (Expense), Net	(1,124)	36
Total revenues and other income	62,756	49,551
Policyholder Benefits and Claims Incurred, Net	10,496	19,355
Expenses:
Intangible amortization	8,763	1,139
General and Administrative Expense	38,531	17,575
Interest expense	5,454	0
Total expenses	77,863	52,790
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	(15,107)	(3,239)
Provision (benefit) for income taxes from continuing operations	(617)	130
Net Income (Loss) Attributable to Nonredeemable Noncontrolling Interest	(1,654)	(701)
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	(14,490)	(3,369)
Net income (loss) attributable to Ambac shareholders	(44,737)	20,771
Other comprehensive income (loss), after tax
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	(14,490)	(3,369)
Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, after Tax	18,606	(7,017)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax	36,220	(7,770)
Other Comprehensive Income (Loss), Financial Liability, Fair Value Option, Unrealized Gain (Loss) Arising During Period, after Tax	442	(253)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	0	(380)
Total other comprehensive income (loss), net of income tax	55,268	(15,420)
Total comprehensive income, net of income tax	10,531	5,351
Total comprehensive income attributable to shareholders	4,625	4,650
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Noncontrolling Interest	$ (1,654)	$ (701)
Earnings Per Share, Basic	$ (1.22)	$ 0.44
Earnings Per Share, Diluted	$ (1.22)	$ 0.44
Weighted Average Number of Shares Outstanding, Basic	47,313,012	45,827,076
Weighted Average Number of Shares Outstanding, Diluted	47,313,012	45,827,076
Premiums Earned, Net	$ 15,678	$ 25,579
Contractually Specified Servicing Fee, Late Fee, and Ancillary Fee Earned in Exchange for Servicing Financial Asset	3,652	2,567
Deferred Policy Acquisition Costs, Amortization Expense	3,841	4,424
General and Administrative Expense	38,531	17,575
Insurance Commissions	10,365	9,822
Unrealized (loss) gain on securities, taxes	645	611
Gain (loss) on foreign currency translation, taxes	0	0
Other Comprehensive Income (Loss), Financial Liability, Fair Value Option, after Reclassification Adjustment, Tax	147	(84)
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Plan Amendments, Tax Effect	0	0
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Noncontrolling Interest	(4,252)	0
Depreciation	413	475
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	(30,247)	24,140
Net income attributable to common shareholders	(44,737)	20,771
Net Income (Loss) from Continuing Operations Available to Common Shareholders, Basic	(16,144)	(4,070)
Net Income (Loss) from Discontinued Operations Available to Common Shareholders, Basic	$ (30,247)	$ 24,140
Income (Loss) from Continuing Operations, Per Basic Share	$ (0.58)	$ (0.09)
Income (Loss) from Continuing Operations, Per Diluted Share	(0.58)	(0.09)
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share	(0.64)	0.53
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share	$ (0.64)	$ 0.53
Net Income (Loss) Available to Common Stockholders, Basic	$ (46,391)	$ 20,070
Fee Income	4,964	0
Depreciation, Depletion and Amortization	9,176	$ 1,614
Discontinued Operations, Held-for-Sale or Disposed of by Sale | Ambac Assurance Corporation [Member]
Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax	(14,496)
Discontinued Operation, Income (Loss) from Discontinued Operation During Phase-out Period, Net of Tax	$ 14,496