Junior Surplus Notes issued by the Segregated Account of Ambac Assurance to Ambac upon Ambac's emergence from bankruptcy. These Junior Surplus notes will be includable in surplus for statutory accounting purposes as prescribed or permitted by state laws and regulations.

No definition available.

Schedule II - Condensed Financial Information of Registrant (Parent Company Only) - Condensed Balance Sheet (Detail) (USD $) In Thousands, unless otherwise specified	Apr. 30, 2013	Dec. 31, 2013 Successor Ambac [Member]	Apr. 30, 2013 Successor Ambac [Member]	Apr. 30, 2013 Predecessor Ambac [Member]	Dec. 31, 2012 Predecessor Ambac [Member]	Dec. 31, 2013 Ambac Financial Group, Inc Parent Company Only [Member] Successor Ambac [Member]	Apr. 30, 2013 Ambac Financial Group, Inc Parent Company Only [Member] Successor Ambac [Member]	Dec. 31, 2012 Ambac Financial Group, Inc Parent Company Only [Member] Predecessor Ambac [Member]	Dec. 31, 2011 Ambac Financial Group, Inc Parent Company Only [Member] Predecessor Ambac [Member]
Assets:
Fixed income securities, at fair value (amortized cost of $28,149 for 2013)		$ 5,885,316			$ 5,402,395	$ 28,145
Junior surplus note of Ambac Assurance Segregated Account						177,194
Short-term investments, at cost (approximates fair value)		271,118			661,219	8,319		30,316
Cash		77,370	152,951	254,851	43,837	43		41
Investment in subsidiaries						473,215		(2,220,724)
Investment income due and accrued		37,663	37,961	37,961	39,742	11,959		11
Other assets		35,927	54,821	54,821	39,715	4,936		6,441
Reorganization value allocated to assets	28,853,435	27,106,939	28,853,435	26,969,994	27,085,265	703,811		(2,183,915)
Liabilities:
Liabilities subject to compromise				1,704,641	1,704,904			1,704,904
Current taxes		738		97,490	96,778			1,900
Accounts payable and other liabilities						828		16,773
Total liabilities	28,393,020	26,128,517	28,393,020	29,444,265	30,332,232	828		1,723,612
Stockholders' equity (deficit):
Preferred stock, value
Common stock, value		450				450		3,080
Additional paid-in capital		185,672			2,172,027	185,672		2,172,027
Accumulated other comprehensive income		11,661		800,260	625,385	11,661		625,385
Retained earnings (accumulated deficit)		505,219		(5,697,961)	(6,297,264)	505,219		(6,297,264)
Common stock held in treasury at cost		(19)		(410,695)		(19)		(410,755)
Total Ambac Financial Group, Inc. stockholders' equity (deficit)		702,983	185,000	(3,133,289)	(3,907,527)	702,983	185,000	(3,907,527)	(3,812,975)
Total liabilities and stockholders' equity (deficit)		$ 27,106,939	$ 28,853,435	$ 26,969,994	$ 27,085,265	$ 703,811		$ (2,183,915)