Consolidated Statements of Stockholders' Equity (USD $) In Thousands	Successor Ambac [Member]	Successor Ambac [Member] Retained Earnings / Accumulated Deficit [Member]	Successor Ambac [Member] Accumulated Other Comprehensive Income [Member]	Successor Ambac [Member] Preferred Stock [Member]	Successor Ambac [Member] Common Stock [Member]	Successor Ambac [Member] Paid-in Capital [Member]	Successor Ambac [Member] Common Stock Held in Treasury, at Cost [Member]	Successor Ambac [Member] Noncontrolling Interest [Member]	Predecessor Ambac [Member]	Predecessor Ambac [Member] Retained Earnings / Accumulated Deficit [Member]	Predecessor Ambac [Member] Accumulated Other Comprehensive Income [Member]	Predecessor Ambac [Member] Preferred Stock [Member]	Predecessor Ambac [Member] Common Stock [Member]	Predecessor Ambac [Member] Paid-in Capital [Member]	Predecessor Ambac [Member] Common Stock Held in Treasury, at Cost [Member]	Predecessor Ambac [Member] Noncontrolling Interest [Member]
Beginning balance at Dec. 31, 2011									$ (3,149,533)	$ (6,039,922)	$ 463,259		$ 3,080	$ 2,172,027	$ (411,419)	$ 663,442
Total comprehensive income (loss)									(605,846)	(557,798)	(45,666)					(2,382)
Stock-based compensation									(664)	(664)
Shares issued under equity plans									664						664
Ending balance at Jun. 30, 2012									(3,755,379)	(6,598,384)	417,593		3,080	2,172,027	(410,755)	661,060
Beginning balance at Mar. 31, 2012
Total comprehensive income (loss)									(841,737)
Ending balance at Jun. 30, 2012									(3,755,379)				3,080	2,172,027
Beginning balance at Dec. 31, 2012									(3,246,967)	(6,297,264)	625,385		3,080	2,172,027	(410,755)	660,560
Total comprehensive income (loss)									3,522,382	3,349,049	174,875					(1,542)
Stock-based compensation									(60)	(60)
Shares issued under equity plans									60						60
Elimination of Predecessor Ambac Shareholder equity accounts and noncontrolling interest adjustment									(800,260)	2,948,275	(800,260)		(3,080)	(2,172,027)	410,695	(383,603)
Ending balance at Apr. 30, 2013					450				275,415							275,415
Beginning balance at Mar. 31, 2013
Total comprehensive income (loss)									3,145,485
Elimination of Predecessor Ambac Shareholder equity accounts and noncontrolling interest adjustment									(800,260)
Ending balance at Apr. 30, 2013	460,415				450	184,550		275,415	275,415
Issuance of new equity in connection with emergence from Chapter 11	185,000				450	184,550
Total comprehensive income (loss)	101,637	205,681	(103,507)					(537)
Warrants exercised	15					15
Ending balance at Jun. 30, 2013	$ 562,067	$ 205,681	$ (103,507)		$ 450	$ 184,565		$ 274,878