Investments (Gains And Losses Due To Changes In Fair Value) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Investments [Line Items]
Gains and losses due to changes in fair value of investment	$ 31,289	$ 46,580	$ 395,482
Fixed Maturity Securities [Member]
Investments [Line Items]
Gains and losses due to changes in fair value of investment	62,149	967	261,866
Equity Securities [Member]
Investments [Line Items]
Gains and losses due to changes in fair value of investment	(30,879)	45,659	133,580
Short-Term Investments [Member]
Investments [Line Items]
Gains and losses due to changes in fair value of investment	$ 19	$ (46)	$ 36

The net change in the difference between the fair value and the carrying value, or in the comparative fair values, of investments, not including unrealized gains or losses on securities separately or otherwise categorized as trading, available-for-sale, or held-to-maturity, held at each balance sheet date and included in earnings for the period.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 28

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3602-108585

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration