Investments (Net Realized Investments Gains) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Investments [Line Items]
Net realized investment gains (losses)	$ 66,380	$ 58,397	$ 57,089
Fixed Maturity Securities [Member]
Investments [Line Items]
Net realized investment gains (losses)	47,707	54,112	5,909
Equity Securities [Member]
Investments [Line Items]
Net realized investment gains (losses)	16,679	(4,854)	46,547
Short-Term Investments [Member]
Investments [Line Items]
Net realized investment gains (losses)	(686)	139	18
Option [Member]
Investments [Line Items]
Net realized investment gains (losses)	$ 2,680	$ 9,000	$ 4,615

The net realized gains or losses on investments during the period, not including gains or losses on securities separately or otherwise categorized as trading, available-for-sale, or held-to-maturity.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-04.3(a))

-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 325

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6485959&loc=d3e22529-158502

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph 3

-Subparagraph a

-Article 7

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