Investments (HTM Fixed Maturity Securities by Contractual Maturity) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Investments [Abstract]
Due in one year or less Carrying Value	$ 105,662
Due after one year through five years Carrying Value	419,074
Due after five years through 10 years Carrying Value	69,198
Due after 10 years Carrying Value	6,782
Total HTM fixed maturity securities Carrying Value	600,716	712,348
Due in one year or less Fair Value	110,275
Due after one year through five years Fair Value	449,498
Due after five years through 10 years Fair Value	78,018
Due after 10 years Fair Value	8,244
Total HTM fixed maturity securities Fair Value	$ 646,035