Investments Classified by Maturity Date (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Debt Maturities, within One Year, Amortized Cost Basis, Percent of Total	32.30%
Available-for-sale Securities, Debt Maturities, within One Year, Fair Value, Percent of Total	31.00%
Available-for-sale Securities, Debt Maturities, after One Through Five Years, Amortized Cost Basis, Percent of Total	19.90%
Available-for-sale Securities, Debt Maturities, after One Through Five Years, Fair Value, Percent of Total	19.60%
Available-for-sale Securities, Debt Maturities, after Five Through Ten Years, Amortized Cost Basis, Percent of Total	32.30%
Available-for-sale Securities, Debt Maturities, after Five Through Ten Years, Fair Value, Percent of Total	33.40%
Available-for-sale Securities, Debt Maturities, after Ten Years, Amortized Cost Basis, Percent of Total	15.50%
Available-for-sale Securities, Debt Maturities, after Ten Years, Fair Value, Percent of Total	16.00%
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Percent of Total	100.00%
Available-for-sale Securities, Fair Value Disclosure	$ 127,371	$ 124,259
Available-for-sale Securities, Fair Value Disclosure, Percent of Total	100.00%
Fixed Maturities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Amortized Cost Basis	38,295
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Fair Value	38,181
Available-for-sale Securities, Debt Maturities, Year Two Through Five, Amortized Cost Basis	23,501
Available-for-sale Securities, Debt Maturities, Year Two Through Five, Fair Value	24,041
Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Amortized Cost Basis	38,205
Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Fair Value	41,217
Available-for-sale Securities, Debt Maturities, after Ten Years, Amortized Cost Basis	18,372
Available-for-sale Securities, Debt Maturities, after Ten Years, Fair Value	19,838
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis	118,373
Available-for-sale Securities, Fair Value Disclosure	$ 123,277	$ 120,378