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Investments - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified | 3 Months Ended |
--- | --- | ---
Mar. 31, 2013 Security | Mar. 31, 2012 | Dec. 31, 2012
Investments [Line Items] |  |  |
Unrealized losses of one security under closed-block life insurance issuance | $ 3,431 |  |
12 Months or Longer, Gross Unrealized Loss | 61,709 |  | 70,164
Unrealized losses of one security of large diversified financial services company | 2,375 |  |
Period of unrealized loss position on large diversified financial services company | 69 months |  |
Period of unrealized loss position on security secured by IRS facility lease payments | 63 months |  |
Number of individual Alt-A securities | 15 |  |
Unrealized losses on security secured by IRS facility lease payments | 28,912 |  |
Investment realized losses | 46,060 | 392 |
Securities fair value | 6,929 |  | 6,945
Fair value of securities held by bankruptcy remote trust | 218,735 |  | 201,329
Other investments | (543) |  |
Corporate obligations [Member] |  |  |
Investments [Line Items] |  |  |
12 Months or Longer, Gross Unrealized Loss | 6,868 |  |
National Century Financial Enterprises, Inc. [Member] |  |  |
Investments [Line Items] |  |  |
Investment realized losses | 150,201 |  |
Investment in asset backed notes | 174,500 |  |
Cash recoveries | 39,978 |  |
Minimum [Member] |  |  |
Investments [Line Items] |  |  |
Period of unrealized loss position on closed-block life insurance issuance | 45 months |  |
Maximum [Member] |  |  |
Investments [Line Items] |  |  |
Period of unrealized loss position on closed-block life insurance issuance | 63 months |  |
Below investment grade securities and non-rated securities [Member] |  |  |
Investments [Line Items] |  |  |
Fair value of below investment grade securities and non-rated securities | 143,145 |  | 192,190
Gross unrealized loss | 38,994 |  | 43,934
Residential mortgage-backed securities [Member] |  |  |
Investments [Line Items] |  |  |
12 Months or Longer, Gross Unrealized Loss | 10,328 |  | 15,236
Asset-backed Securities [Member] |  |  |
Investments [Line Items] |  |  |
12 Months or Longer, Gross Unrealized Loss | $ 44,426 |  |

X
- Definition Number of months closed block life insurance issuance in a continuous unrealized loss position. + References No definition available. + Details
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- Definition Number of months an issuance of a large diversified financial services company that is in a continuous unrealized loss position. + References No definition available. + Details
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- Definition Number of months a security that is secured by IRS facility lease payments is in a continuous unrealized loss position. + References No definition available. + Details
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- Definition Aggregate losses for a closed block life insurance issuance in a continuous unrealized loss position for twelve months or longer. + References No definition available. + Details
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- Definition Aggregate losses for an issuance of a large diversified financial services company that is in a continuous unrealized loss position for twelve months or longer. + References No definition available. + Details
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- Definition Number of Alt-A securities in a continuous unrealized loss position greater than twelve months. + References No definition available. + Details
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- Definition Aggregate losses for related to a security that is secured by IRS facility lease payments in a continuous unrealized loss position for twelve months or longer. + References No definition available. + Details
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- Details
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- Definition Fair Value of securities held to collateralize and fund repayment of debt issued through a resecuritization transaction. + References No definition available. + Details
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- Definition Investments in notes or bonds that are collateralized by a specific group of underlying assets owned by the issuer of the notes or bonds which are short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Cash Equivalents -URI http://asc.fasb.org/extlink&oid=6507016 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 8, 9 -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. + Details
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- Definition Amount of the excess of amortized cost basis over fair value of securities that have been in a loss position for twelve months or longer for securities which are categorized neither as held-to-maturity nor trading securities. + References No definition available. + Details
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- Definition The net realized gains or losses on investments during the period, not including gains or losses on securities separately or otherwise categorized as trading, available-for-sale, or held-to-maturity. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-04.3(a)) -URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 325 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6485959&loc=d3e22529-158502 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 04 -Paragraph 3 -Subparagraph a -Article 7 + Details
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