Investment in Life Settlements - Additional Information (Parenthetical) (Detail)	Sep. 30, 2012 Contract
Investments, All Other Investments [Abstract]
Life settlement contracts, number of contracts with fair value	166
Total number of Life Settlement Contracts	256
Life settlement contracts, number of contracts with no fair value	90

Number of life settlement contracts accounted for under the fair value method.

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Life Settlement Contract

-URI http://asc.fasb.org/extlink&oid=6516907

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 325

-SubTopic 30

-Section 50

-Paragraph 8

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6385267&loc=d3e42732-111610

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

-Publisher FASB

-Name FASB Staff Position (FSP)

-Number FTB85-4-1

-Paragraph 17

-Subparagraph a

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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

Name:	us-gaap_LifeSettlementContractsFairValueMethodNumberOfContracts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant