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Fair Value Measurements (Changes in Fair Value of Securities Using Level 3 Inputs) (Details) (USD $) | 12 Months Ended
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Dec. 31, 2013 | Dec. 31, 2012
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |  |  |
Fair Value, Beginning Balance | $ 42,277,000 |  | $ 27,910,000 |
Total net (losses) gains for the period included in OCI | 4,089,000 | [1] | 1,089,000 | [1]
Total net (losses) gains for the period included in net income | (1,195,000) | [2],[3] | 0 | [2],[3]
Purchases | 0 |  | 12,911,000 |
Sales | 0 |  | 0 |
Issuances | 0 |  | 0 |
Settlements | (4,660,000) |  | (3,742,000) |
Transfers into Level 3 | 0 |  | 12,642,000 |
Transfers out of Level 3 | (37,611,000) |  | (8,533,000) |
Fair Value, Ending Balance | 2,900,000 |  | 42,277,000 |
Receivable Related To Sale Of Subsidiary | 1,000,000 |  |  |
Number of non- public equity securities transferred into level 3 |  |  | 2 |
Equity Securities [Member] |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |  |  |
Fair Value, Beginning Balance | 3,607,000 |  | 0 |
Total net (losses) gains for the period included in OCI | 3,935,000 | [1] | 0 | [1]
Total net (losses) gains for the period included in net income | 0 | [2],[3] | 0 | [2],[3]
Purchases | 0 |  | 0 |
Sales | 0 |  | 0 |
Issuances | 0 |  | 0 |
Settlements | 0 |  | 0 |
Transfers into Level 3 | 0 |  | 3,607,000 |
Transfers out of Level 3 | (4,642,000) |  | 0 |
Fair Value, Ending Balance | 2,900,000 |  | 3,607,000 |
AFS Fixed Maturity Securities [Member] | U.S. Government and Government Agencies [Member] |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |  |  |
Fair Value, Beginning Balance | 19,789,000 |  | 21,741,000 |
Total net (losses) gains for the period included in OCI | (537,000) | [1] | (22,000) | [1]
Total net (losses) gains for the period included in net income | (76,000) | [2],[3] | (193,000) | [2],[3]
Purchases | 0 |  | 0 |
Sales | 0 |  | 0 |
Issuances | 0 |  | 0 |
Settlements | (1,847,000) |  | (1,737,000) |
Transfers into Level 3 | 0 |  | 0 |
Transfers out of Level 3 | (17,329,000) |  | 0 |
Fair Value, Ending Balance | 0 |  | 19,789,000 |
AFS Fixed Maturity Securities [Member] | Corporate Securities [Member] |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |  |  |
Fair Value, Beginning Balance | 2,946,000 |  | 2,603,000 |
Total net (losses) gains for the period included in OCI | (7,000) | [1] | 185,000 | [1]
Total net (losses) gains for the period included in net income | 0 | [2],[3] | 0 | [2],[3]
Purchases | 0 |  | 0 |
Sales | 0 |  | 0 |
Issuances | 0 |  | 0 |
Settlements | (168,000) |  | (630,000) |
Transfers into Level 3 | 0 |  | 788,000 |
Transfers out of Level 3 | (2,771,000) |  | 0 |
Fair Value, Ending Balance | 0 |  | 2,946,000 |
AFS Fixed Maturity Securities [Member] | Asset-backed Securities [Member] |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |  |  |
Fair Value, Beginning Balance | 6,068,000 |  | 0 |
Total net (losses) gains for the period included in OCI | (74,000) | [1] | 68,000 | [1]
Total net (losses) gains for the period included in net income | 0 | [2],[3] | 0 | [2],[3]
Purchases | 0 |  | 7,300,000 |
Sales | 0 |  | 0 |
Issuances | 0 |  | 0 |
Settlements | 0 |  | 0 |
Transfers into Level 3 | 0 |  | 0 |
Transfers out of Level 3 | (5,994,000) |  | (1,300,000) |
Fair Value, Ending Balance | 0 |  | 6,068,000 |
AFS Fixed Maturity Securities [Member] | Commercial Mortgage-backed Securities (CMBS) [Member] |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |  |  |
Fair Value, Beginning Balance | 7,162,000 |  | 354,000 |
Total net (losses) gains for the period included in OCI | 772,000 | [1] | 858,000 | [1]
Total net (losses) gains for the period included in net income | 361,000 | [2],[3] | (51,000) | [2],[3]
Purchases | 0 |  | 5,611,000 |
Sales | 0 |  | 0 |
Issuances | 0 |  | 0 |
Settlements | (2,420,000) |  | (624,000) |
Transfers into Level 3 | 0 |  | 8,247,000 |
Transfers out of Level 3 | (5,875,000) |  | (7,233,000) |
Fair Value, Ending Balance | 0 |  | 7,162,000 |
Receivable For Proceeds From Divestiture Of Businesses [Member] |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |  |  |
Fair Value, Beginning Balance | 2,705,000 |  | 3,212,000 |
Total net (losses) gains for the period included in OCI | 0 | [1] | 0 | [1]
Total net (losses) gains for the period included in net income | (1,480,000) | [2],[3] | 244,000 | [2],[3]
Purchases | 0 |  | 0 |
Sales | 0 |  | 0 |
Issuances | 0 |  | 0 |
Settlements | (225,000) |  | (751,000) |
Transfers into Level 3 | 0 |  | 0 |
Transfers out of Level 3 | (1,000,000) |  | 0 |
Fair Value, Ending Balance | 0 |  | 2,705,000 |
Fair Value, Inputs, Level 3 [Member] | AFS Fixed Maturity Securities [Member] |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |  |  |
Transfers into Level 3 |  |  | 9,000,000 |
Transfers out of Level 3 | $ (32,000,000) |  | $ (8,500,000) |
[1] | Amounts are reported in “Unrealized holding (losses) gains arising during period” on the Consolidated Statements of Comprehensive Income.
[2] | For the receivable related to the sale of Selective HR, amounts in “Loss on disposal of discontinued operations, net of tax” relate to an impairment charge and amounts in “Other income” relate to interest accretion on the Consolidated Statements of Income.
[3] | Amounts are reported in “Net realized gains” for realized gains and losses and “Net investment income earned” for amortization of securities on the Consolidated Statements of Income.

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- Definition Amount of gain (loss) recognized in the income statement for financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + 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)(1) -URI http://asc.fasb.org/extlink&oid=25499696&loc=d3e19207-110258 + Details
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