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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, 2011 years securities | Dec. 31, 2010
Fair value, Beginning balance | $ 5,187,000 |  | $ 12,300,000 |
Total net gains (losses) for the period included in OCI | 425,000 | [1] | 1,840,000 | [1]
Total net gains (losses) for the period included in net income | (977,000) | [2],[3] | (5,419,000) | [2],[3]
Purchases | 0 |  |  |
Sales | 0 |  |  |
Issuances | 0 |  |  |
Settlements | (930,000) |  |  |
Purchases, sales, issuances, and settlements (net) |  |  | 751,000 |
Net transfers in and/or out of Level 3 | 0 |  | (4,285,000) |
Fair value, Ending balance | 3,705,000 |  | 5,187,000 |
Reduction in the value of our receivable for the expected proceeds from the sale of Selective HR | 1,000,000 |  |  |
Period over which proceeds are scheduled to be received | 10 |  |  |
Interest accretion on the receivable | 300,000 |  |  |
Asset-backed Securities ("ABS") [Member] | AFS Fixed Maturity Securities [Member] |  |  |  |
Fair value, Beginning balance |  |  | 0 |
Total net gains (losses) for the period included in OCI |  |  | (22,000) | [1]
Total net gains (losses) for the period included in net income |  |  | 0 | [2],[3]
Purchases, sales, issuances, and settlements (net) |  |  | 2,737,000 |
Net transfers in and/or out of Level 3 |  |  | (2,715,000) |
Fair value, Ending balance |  |  | 0 |
Commercial Mortgage-backed Securities ("CMBS") [Member] | AFS Fixed Maturity Securities [Member] |  |  |  |
Fair value, Beginning balance | 185,000 |  | 0 |
Total net gains (losses) for the period included in OCI | 425,000 | [1] | 1,862,000 | [1]
Total net gains (losses) for the period included in net income | (269,000) | [2],[3] | 41,000 | [2],[3]
Purchases | 0 |  |  |
Sales | 0 |  |  |
Issuances | 0 |  |  |
Settlements | (11,000) |  |  |
Purchases, sales, issuances, and settlements (net) |  |  | (148,000) |
Net transfers in and/or out of Level 3 | 0 |  | (1,570,000) |
Fair value, Ending balance | 330,000 |  | 185,000 |
Receivable For Proceeds From Divestiture Of Businesses [Member] |  |  |  |
Fair value, Beginning balance | 5,002,000 |  | 12,300,000 |
Total net gains (losses) for the period included in OCI | 0 | [1] | 0 | [1]
Total net gains (losses) for the period included in net income | (708,000) | [2],[3] | (5,460,000) | [2],[3]
Purchases | 0 |  |  |
Sales | 0 |  |  |
Issuances | 0 |  |  |
Settlements | (919,000) |  |  |
Purchases, sales, issuances, and settlements (net) |  |  | (1,838,000) |
Net transfers in and/or out of Level 3 | 0 |  | 0 |
Fair value, Ending balance | $ 3,375,000 |  | $ 5,002,000 |
[1] | Amounts are reported in "Other net unrealized gains on investment securities, net of deferred income tax" on the Consolidated Statements of Stockholders' Equity.
[2] | Amounts are reported in "Net realized investment gains (losses)" for realized gains and losses and "Net investment income earned" for amortization for the CMBS securities on the Consolidated Statements of Income.
[3] | Amounts are reported in either "Loss on disposal of discontinued operations, net of tax" or "Other income" for the receivable related to sale of Selective HR on the Consolidated Statements of Income. Amounts in "Loss on disposal of discontinued operations, net of tax" relate to charges to reduce the fair value of our receivable and amounts in "Other income" reflect interest accretion on the receivable.

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