Fresh Start Accounting - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Mar. 19, 2012
Fresh-Start Adjustment [Line Items]
Minimum percentage of shares held by voter before confirmation of reorganization	50.00%
Company's reorganization value		$ 76.6
Loss contract fair market value reserve	$ 63.1	$ 63.1

Amount attributed to the reconstituted entity, as well as the expected net realizable value of those assets that will be disposed before reconstitution occurs.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 852

-SubTopic 10

-Section 55

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6585303&loc=d3e56239-112766

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

-Publisher AICPA

-Name Statement of Position (SOP)

-Number 90-7

-Paragraph 37, 38, 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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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

-Glossary Reorganization Value

-URI http://asc.fasb.org/extlink&oid=6523519

Reference 4: 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 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 852

-SubTopic 10

-Section 05

-Paragraph 15

-URI http://asc.fasb.org/extlink&oid=6458260&loc=d3e54813-112758

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