Investments - Troubled Debt Restructuring (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012 contract	Dec. 31, 2011 contract
Investments, Debt and Equity Securities [Abstract]
Number of troubled debt restructuring contracts	0	1
Troubled debt restructurings pre-modification carrying value		$ 13.0
Troubled debt restructurings post-modification carrying value		$ 12.9

Number of financing receivables that have been modified by troubled debt restructurings.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 33

-URI http://asc.fasb.org/extlink&oid=7512638&loc=SL6953676-111524

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- Definition

Amount of investment in financing receivables (after modification) modified by troubled debt restructurings.

+ References

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- Definition

Amount of investment in financing receivables (before modification) modified by troubled debt restructurings.

+ References

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