Fair Value (Narrative) (Details) $ in Thousands	12 Months Ended
Dec. 31, 2015 USD ($) security	Dec. 31, 2014 USD ($)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of public equity portfolio	$ 131,219	$ 96,890
Transfers between Level 1 and Level 2	0
Transfers from level 3	8,244	14,007
Available For Sale Securities Debt Securities Market Value	5,356,477	5,293,411
Parent Company [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Available For Sale Securities Debt Securities Market Value	$ 65,441	$ 9,040
Private Placement [Member] \| Unavailability Of Prices [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Number of securities \| security	2
Available For Sale Securities Debt Securities Market Value	$ 3,593

Amount of debt securities categorized neither as held-to-maturity nor trading, held at market value.

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- Definition

Number Of Securities

+ References

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- Definition

Public equity portfolio fair value disclosure.

+ References

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- Definition

Amount of transfers of assets measured on a recurring basis out of Level 1 of the fair value hierarchy into Level 2.

+ 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 (bb)
-URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19207-110258

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

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- Definition

Amount of transfer of financial instrument classified as an asset into (out of) level 3 of the fair value hierarchy.

+ References

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