Significant Accounting Policies - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	Apr. 30, 2013	Apr. 30, 2013 Variable Interest Entity [Member]	Jun. 30, 2013 Successor Ambac [Member]
Goodwill [Line Items]
Goodwill			$ 514,511
Intangible assets at fair value	$ 164,520	$ 164,520

Amount of goodwill at the balance sheet date after fresh-start adjustments.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 852

-SubTopic 10

-Section 55

-Paragraph 10

-URI http://asc.fasb.org/extlink&oid=6585303&loc=d3e56426-112766

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Statement of Position (SOP)

-Number 90-7

-Paragraph 39, 68

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 852

-SubTopic 10

-Section 50

-Paragraph 7

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6918054&loc=SL2890621-112765

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