Investments (Details 3) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Amortized Cost, Due in one year or less	$ 48,230
Amortized Cost, Due after one year through five years	181,967
Amortized Cost, Due after five years through ten years	111,172
Amortized Cost, Due after ten years	52,156
Debt Maturities, Amortized Cost	397,052
Fair Value, Due in one year or less	48,590
Fair Value, Due after one year through five years	184,767
Fair Value, Due after five years through ten years	110,914
Fair Value, Due after ten years	51,196
Debt Securities, Fair Value	399,069	380,469
Collateralized Mortgage Backed Securities [Member]
Debt Maturities, Amortized Cost	3,527
Debt Securities, Fair Value	$ 3,602