Rollforward of Level 3 Assets Measured on a Recurring Basis (Details) (Fair Value, Measurements, Recurring [Member], Fair Value, Inputs, Level 3 [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Fair Value, Measurements, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Transfers out of level 3	$ (2)	$ (11,830)
Transfers Into level 3	521	9
Settlements	0	(2,747)
Sales	(3,466)	(4,770)
Purchases	1,484	0
Net realized gains (losses) included in realized investment gains, including other-than-temporary impairment losses	(18)	1,446
Level 3 Assets	5,221	6,937	24,998
Net unrealized gains (losses) included in other comprehensive income	$ (235)	$ (169)

Rollforward of Level 3 Assets Measured on a Recurring Basis (Details) (Fair Value, Measurements, Recurring [Member], Fair Value, Inputs, Level 3 [Member], USD $)
In Thousands, unless otherwise specified

12 Months Ended

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2010

Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]

Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]

Transfers out of level 3

$ (2)

$ (11,830)

Transfers Into level 3

521

Settlements

(2,747)

Sales

(3,466)

(4,770)

Purchases

1,484

Net realized gains (losses) included in realized investment gains, including other-than-temporary impairment losses

(18)

1,446

Level 3 Assets

5,221

6,937

24,998

Net unrealized gains (losses) included in other comprehensive income

$ (235)

$ (169)

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- Definition

Amount of gain (loss) recognized in earnings, arising from assets measured at fair value on a recurring basis using unobservable inputs (level 3).

+ References

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- Definition

Amount of gain (loss) recognized in other comprehensive income, arising from assets measured at fair value on a recurring basis using unobservable inputs (level 3).

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- Definition

Purchases that have taken place during the period in relation to assets measured at fair value and categorized within Level 3 of the fair value hierarchy.

+ References

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- Definition

Sales that have taken place during the period in relation to assets measured at fair value and categorized within Level 3 of the fair value hierarchy.

+ References

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- Definition

Settlements that have taken place during the period in relation to assets measured at fair value and categorized within Level 3 of the fair value hierarchy.

+ References

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- Definition

Transfers into assets measured at fair value and categorized within Level 3 of the fair value hierarchy that have taken place during the period.

+ References

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- Definition

Transfers out of assets measured at fair value and categorized within Level 3 of the fair value hierarchy that have taken place during the period.

+ References

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- Definition

This element represents an asset measured at fair value using significant unobservable inputs (Level 3) which is required for reconciliation purposes of beginning and ending balances.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19207-110258

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 157

-Paragraph 32

-Subparagraph c

-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.

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