Financial Guarantee Insurance Contracts - Effect of Reinsurance on Premiums Written and Earned (Detail) (USD $) In Thousands, unless otherwise specified	2 Months Ended	3 Months Ended	6 Months Ended	1 Months Ended	4 Months Ended
	Jun. 30, 2013 Successor Ambac [Member]	Jun. 30, 2014 Successor Ambac [Member]	Jun. 30, 2014 Successor Ambac [Member]	Apr. 30, 2013 Predecessor Ambac [Member]	Apr. 30, 2013 Predecessor Ambac [Member]
Reinsurance Premiums for Insurance Companies, by Product Segment [Line Items]
Direct Premiums Written	$ (34,081)	$ (45,486)	$ (51,252)	$ (10,595)	$ (14,125)
Assumed Reinsurance Premiums Written	0	0	0	0	0
Ceded Reinsurance Premiums Written	(3,038)	(4,967)	(4,511)	(84)	(1,098)
Premiums written, net of reinsurance	(31,043)	(40,519)	(46,741)	(10,511)	(13,027)
Direct Premiums Earned	62,033	68,025	154,209	31,388	138,468
Assumed Reinsurance Premiums Earned	16	23	91	8	32
Ceded Reinsurance Premiums Earned	4,010	3,035	6,740	1,652	8,500
Reinsurance on premiums earned, Net	$ 58,039	$ 65,013	$ 147,560	$ 29,744	$ 130,000