Investments Classified by Maturity Date (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale Securities, Debt Maturities, within One Year, Amortized Cost Basis, Percent of Total	15.30%
Available-for-sale Securities, Debt Maturities, within One Year, Fair Value, Percent of Total	15.30%
Available-for-sale Securities, Debt Maturities, after One Through Five Years, Amortized Cost Basis, Percent of Total	48.80%
Available-for-sale Securities, Debt Maturities, after One Through Five Years, Fair Value, Percent of Total	48.70%
Available-for-sale Securities, Debt Maturities, after Five Through Ten Years, Amortized Cost Basis, Percent of Total	29.90%
Available-for-sale Securities, Debt Maturities, after Five Through Ten Years, Fair Value, Percent of Total	29.80%
Available-for-sale Securities, Debt Maturities, after Ten Years, Amortized Cost Basis, Percent of Total	6.00%
Available-for-sale Securities, Debt Maturities, after Ten Years, Fair Value, Percent of Total	6.20%
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Percent of Total	100.00%
Available-for-sale Securities, Debt Securities	$ 267,420	$ 273,024
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	40,868
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Fair Value	40,930
Available-for-sale Securities, Debt Maturities, Year Two Through Five, Amortized Cost Basis	129,999
Available-for-sale Securities, Debt Maturities, Year Two Through Five, Fair Value	130,057
Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Amortized Cost Basis	79,825
Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Fair Value	79,811
Available-for-sale Securities, Debt Maturities, after Ten Years, Amortized Cost Basis	16,113
Available-for-sale Securities, Debt Maturities, after Ten Years, Fair Value	16,622
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis	266,805
Available-for-sale Securities, Debt Securities	$ 267,420	$ 273,024