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Summary of Significant Accounting Policies (Narrative) (Details) (USD $) | 12 Months Ended
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Dec. 31, 2012 Subsidiary | Dec. 31, 2011 | Dec. 31, 2010
Summary Of Significant Accounting Policies [Line Items] |  |  |
Number of insurance companies | 13 |  |
Percentage of direct premiums written as private passenger automobile lines of insurance | 80.00% | 80.00% | 80.00%
Percentage of private passenger automobile premiums written in California | 78.00% | 77.00% | 77.00%
Percentage by which dividend income on non redeemable preferred stock, partnership, common stock is partially tax-sheltered | 70.00% |  |
Other liabilities | $ 153,972,000 | $ 149,007,000 |
Marketable securities, fixed maturities | 42,800,000 |  |
Marketable securities, equity securities | 11,300,000 |  |
Insurance companies security deposits | 16,000,000 | 18,000,000 |
Deferred policy acquisition cost amortization | 477,788,000 | 481,721,000 | 505,565,000
Advertising expenses | 19,000,000 | 21,000,000 | 30,000,000
Impairment charges | 0 | 0 | 0
Goodwill impairment loss | 0 |  |
Premiums written, net | 2,650,000,000 | 2,580,000,000 | 2,560,000,000
Broker direct premiums percentage account | 2.00% | 2.00% | 2.00%
Options Granted Prior To 2008 [Member] | Minimum [Member] |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |
Option vesting term, years | 4 years |  |
Options Granted Prior To 2008 [Member] | Maximum [Member] |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |
Option vesting term, years | 5 years |  |
Options Granted Subsequent To January 1, 2008 [Member] |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |
Option vesting term, years | 4 years |  |
Building [Member] | Minimum [Member] |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |
Useful life, in years | 30 years |  |
Building [Member] | Maximum [Member] |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |
Useful life, in years | 40 years |  |
Furniture Equipment And Purchase Software [Member] | Minimum [Member] |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |
Useful life, in years | 3 years |  |
Furniture Equipment And Purchase Software [Member] | Maximum [Member] |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |
Useful life, in years | 7 years |  |
Software [Member] |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |
Useful life, in years | 5 years |  |
Secured Note No1 [Member] |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |
Debt instrument, fair value | 120,000,000 |  |
Secured Note No2 [Member] |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |
Debt instrument, fair value | 20,000,000 |  |
Call Option [Member] |  |  |
Summary Of Significant Accounting Policies [Line Items] |  |  |
Other liabilities | $ 200,000 | $ 700,000 |

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