Investments Classified by Maturity Date (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 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	14.00%
Available-for-sale Securities, Debt Maturities, within One Year, Fair Value, Percent of Total	14.00%
Available-for-sale Securities, Debt Maturities, after One Through Five Years, Amortized Cost Basis, Percent of Total	49.00%
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	34.60%
Available-for-sale Securities, Debt Maturities, after Five Through Ten Years, Fair Value, Percent of Total	34.80%
Available-for-sale Securities, Debt Maturities, after Ten Years, Amortized Cost Basis, Percent of Total	2.40%
Available-for-sale Securities, Debt Maturities, after Ten Years, Fair Value, Percent of Total	2.50%
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Percent of Total	100.00%
Available-for-sale Securities, Debt Securities	$ 329,120	$ 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	45,915
Available-for-sale Securities, Debt Maturities, Next Twelve Months, Fair Value	45,973
Available-for-sale Securities, Debt Maturities, Year Two Through Five, Amortized Cost Basis	160,295
Available-for-sale Securities, Debt Maturities, Year Two Through Five, Fair Value	160,318
Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Amortized Cost Basis	113,271
Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Fair Value	114,693
Available-for-sale Securities, Debt Maturities, after Ten Years, Amortized Cost Basis	7,851
Available-for-sale Securities, Debt Maturities, after Ten Years, Fair Value	8,136
Available-for-sale Securities, Debt Maturities, Amortized Cost Basis	327,332
Available-for-sale Securities, Debt Securities	$ 329,120	$ 273,024