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Adoption of Accounting Pronouncements (Income Statement Statement) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified | 3 Months Ended
--- | ---
Mar. 31, 2012 | Mar. 31, 2011
Policy acquisition costs | $ 127,958 | $ 115,044
Deferred income tax expense | (2,080) | 1,382
Net income | 18,093 | 20,500
Basic net income per share | $ 0.33 | $ 0.38
Diluted net income per share | $ 0.33 | $ 0.37
As Previously Reported [Member] |  |
Policy acquisition costs |  | 113,430
Deferred income tax expense |  | 1,947
Net income |  | 21,549
Basic net income per share |  | $ 0.40
Diluted net income per share |  | $ 0.39
Add: Adjustment for the cumulative effect on prior years of applying retroactively the new method of accounting for deferred policy acquisition costs [Member] |  |
Policy acquisition costs |  | 1,614
Deferred income tax expense |  | (565)
Net income |  | $ (1,049)
Basic net income per share |  | $ (0.02)
Diluted net income per share |  | $ (0.02)

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