Investments Fixed maturities by contractual maturity periods (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Fixed maturities by contractual maturity periods [Abstract]
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Amortized Cost Basis	$ 20,119
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Fair Value	20,207
Available-for-sale Securities, Debt Maturities, Year Two Through Five, Amortized Cost Basis	47,781
Available-for-sale Securities, Debt Maturities, Year Two Through Five, Fair Value	48,934
Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Amortized Cost Basis	1,132
Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Fair Value	1,257
Available-for-sale Securities, Debt Maturities, after Ten Years, Amortized Cost Basis	594
Available-for-sale Securities, Debt Maturities, after Ten Years, Fair Value	612
Available-for-sale Securities, Amortized Cost Basis	69,626
Available-for-sale Securities, Debt Securities	$ 71,010	$ 79,534

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This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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Amount of available-for-sale debt securities at cost, net of adjustments, maturing in the sixth fiscal year through the tenth fiscal year following the latest fiscal year. Adjustments include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings (less any cumulative-effect adjustments, as defined) and fair value hedge accounting adjustments.

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Amount of available-for-sale debt securities at fair value maturing in the sixth fiscal year through the tenth fiscal year following the latest fiscal year.

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Amount of available-for-sale debt securities at cost, net of adjustments, maturing in the second fiscal year through the fifth fiscal year following the latest fiscal year. Adjustments include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings (less any cumulative-effect adjustments, as defined) and fair value hedge accounting adjustments.

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Amount of available-for-sale debt securities at fair value maturing in the second fiscal year through the fifth fiscal year following the latest fiscal year.

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Amount of available-for-sale debt securities at cost, net of adjustments, maturing after the tenth fiscal year following the latest fiscal year. Adjustments include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings (less any cumulative-effect adjustments, as defined) and fair value hedge accounting adjustments.

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Amount of available-for-sale debt securities at fair value maturing after the tenth fiscal year following the latest fiscal year.

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Amount of available-for-sale debt securities at cost, net of adjustments, maturing in the next fiscal year following the latest fiscal year. Adjustments include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings (less any cumulative-effect adjustments, as defined) and fair value hedge accounting adjustments.

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Amount of debt securities categorized neither as held-to-maturity nor trading.

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