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Fair Value Measurements (Changes in Fair Value of Securities Using Level 3 Inputs) (Details) (USD $) | 9 Months Ended | 12 Months Ended
--- | --- | ---
Sep. 30, 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 | 3,966,000 | [1] | 1,089,000 | [2]
Total net (losses) gains for the period included in net income | (1,202,000) | [3],[4] | 0 | [5],[6]
Purchases | 0 |  | 12,911,000 |
Sales | 0 |  | 0 |
Issuances | 0 |  | 0 |
Settlements | (3,843,000) |  | (3,742,000) |
Transfers into Level 3 | 0 |  | 12,642,000 |
Transfers out of Level 3 | (30,727,000) |  | (8,533,000) |
Fair value, Ending balance | 10,471,000 |  | 42,277,000 |
Receivable amount related to sale of subsidiary | 1,000,000 |  |  |
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 | [2]
Total net (losses) gains for the period included in net income | 0 | [3],[4] | 0 | [5],[6]
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] |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items] |  |  |  |
Fair value, Ending balance | 7,600,000 |  | 36,000,000 |
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) | [2]
Total net (losses) gains for the period included in net income | (76,000) | [3],[4] | (193,000) | [5],[6]
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 | [2]
Total net (losses) gains for the period included in net income | 0 | [3],[4] | 0 | [5],[6]
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 | (106,000) | [1] | 68,000 | [2]
Total net (losses) gains for the period included in net income | 0 | [3],[4] | 0 | [5],[6]
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 | 0 |  | (1,300,000) |
Fair value, Ending balance | 5,962,000 |  | 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 | 681,000 | [1] | 858,000 | [2]
Total net (losses) gains for the period included in net income | 354,000 | [3],[4] | (51,000) | [5],[6]
Purchases | 0 |  | 5,611,000 |
Sales | 0 |  | 0 |
Issuances | 0 |  | 0 |
Settlements | (1,603,000) |  | (624,000) |
Transfers into Level 3 | 0 |  | 8,247,000 |
Transfers out of Level 3 | (4,985,000) |  | (7,233,000) |
Fair value, Ending balance | 1,609,000 |  | 7,162,000 |
Receivable For Proceeds From Divestiture Of Business [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 | [2]
Total net (losses) gains for the period included in net income | (1,480,000) | [3],[4] | 244,000 | [5],[6]
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 | $ 25,100,000 |  |  |
[1] | Amounts are reported in “Unrealized holding gains (losses) arising during period” on the Unaudited Consolidated Statements of Comprehensive Income.
[2] | Amounts are reported in “Unrealized holding gains arising during period” on the Consolidated Statements of Comprehensive Income in our 2012 Annual Report.
[3] | Amounts are reported in “Net realized gains (losses)” for realized gains and “Net investment income earned” for amortization of securities on the Unaudited Consolidated Statements of Income.
[4] | 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 Unaudited Consolidated Statements of Income.
[5] | Amounts are reported in “Net realized gains (losses)” for realized gains and losses and “Net investment income earned” for amortization for the CMBS securities on the Consolidated Statements of Income in our 2012 Annual Report.
[6] | Amounts are reported in “Other income” for the receivable related to the sale of Selective HR on the Consolidated Statements of Income in our 2012 Annual Report and are related to interest accretion on the receivable.

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