Investments (Details 1) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012
Amortized cost and estimated fair value of fixed maturity securities by contractual maturity
Due in one year or less, Amortized cost	$ 31,105
Due after one year through five years, Amortized cost	107,180
Due after five years through ten years, Amortized cost	160,483
Due after ten years, Amortized cost	73,340
Mortgage and asset-backed securities, Amortized cost	359,923
Amortized cost, Total	732,031
Due in one year or less, Estimated fair value	31,429
Due after one year through five years, Estimated fair value	114,638
Due after five years through ten years, Estimated fair value	178,648
Due after ten years, Estimated fair value	91,985
Mortgage and asset-backed securities, Estimated fair value	379,648
Estimated fair value, Total	$ 796,348