Investments (Details 3) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Amortized Cost, Due in one year or less	$ 50,324
Amortized Cost, Due after one year through five years	163,456
Amortized Cost, Due after five years through ten years	112,290
Amortized Cost, Due after ten years	51,277
Debt Maturities, Amortized Cost	380,495
Fair Value, Due in one year or less	50,937
Fair Value, Due after one year through five years	166,452
Fair Value, Due after five years through ten years	113,254
Fair Value, Due after ten years	50,400
Debt Securities, Fair Value	384,288	380,469
Collateralized Mortgage Backed Securities [Member]
Debt Maturities, Amortized Cost	3,148
Debt Securities, Fair Value	$ 3,245	$ 4,137