Fair Value (Schedule Of Realized Gains (Losses) Using Level 3 Inputs) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended
Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Dividends And Other Investment Income [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Realized gains (losses) from Level 3 inputs	$ 3,859	$ 1,619	$ 4,516	$ 3,250
Fixed Income Securities Gains (Losses), Net [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Realized gains (losses) from Level 3 inputs	$ 5,470	$ (2,465)	$ 6,137	$ (2,570)

This item represents the amount of the total realized and unrealized gains or losses for the period which are included in the statement of income (or changes in net assets) in investment income; the fair value of which assets was or is measured on a recurring basis using significant unobservable inputs (Level 3).

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 157

-Paragraph 32

-Subparagraph c(1)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)

-URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19207-110258

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration