Consolidated Statements of Total Comprehensive Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014 Successor Ambac [Member]	Mar. 31, 2013 Predecessor Ambac [Member]
Revenues:
Net premiums earned	$ 82,547	$ 100,256
Net investment income:
Securities available-for-sale and short-term	68,807	85,057
Other investments	1,994	(543)
Total net investment income	70,801	84,514
Other-than-temporary impairment losses:
Total other-than-temporary impairment losses	(10,392)	0
Portion of loss recognized in other comprehensive income	0	0
Net other-than-temporary impairment losses recognized in earnings	(10,392)	0
Net realized investment gains (losses)	16,289	46,060
Change in fair value of credit derivatives:
Realized gains (losses) and other settlements	775	2,509
Unrealized gains (losses)	6,607	10,278
Net change in fair value of credit derivatives	7,382	12,787
Derivative products	(53,841)	(569)
Other income	1,894	9,498
(Loss) income on variable interest entities	(5,542)	38,326
Total revenues before expenses and reorganization items	109,138	290,872
Expenses:
Losses and loss expenses (benefit)	(140,011)	(51,135)
Insurance intangible amortization	31,714	0
Underwriting and operating expenses	25,786	33,874
Interest expense	32,328	23,165
Total (benefit) expenses before reorganization items	(50,183)	5,904
Pre-tax income (loss) from continuing operations before reorganization items	159,321	284,968
Reorganization items	23	2,059
Pre-tax income (loss) from continuing operations	159,298	282,909
Provision for income taxes	3,249	657
Net income (loss)	156,049	282,252
Less: net gain (loss) attributable to noncontrolling interest	107	(47)
Net income (loss) attributable to common shareholders	155,942	282,299
Other comprehensive income (loss), after tax:
Net income (loss)	156,049	282,252
Unrealized gain (loss) on securities, net of deferred income taxes of $0	88,722	94,098
Gain (loss) on foreign currency translation, net of deferred income taxes of $0	4,284	(261)
Changes to postretirement benefit, net of tax of $0	(204)	808
Total other comprehensive income, net of tax	92,802	94,645
Total comprehensive income (loss)	248,851	376,897
Less: comprehensive gain (loss) attributable to the noncontrolling interest:
Noncontrolling interest in subsidiaries’ earnings	107	(47)
Currency translation adjustments	46	(41)
Total comprehensive income (loss) attributable to Ambac Financial Group, Inc.	$ 248,698	$ 376,985
Net income (loss) per share attributable to Ambac Financial Group, Inc. common shareholders (in dollars per share)	$ 3.46	$ 0.93
Net income (loss) per diluted share attributable to Ambac Financial Group, Inc. common shareholders (in dollars per share)	$ 3.31	$ 0.93