Investments (Schedule of Amortized Cost and Estimated Fair Value of Debt Securities by Contractual Maturities) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Schedule of Investments [Line Items]
Due in one year or less, Amortized Cost	$ 64,572
Due after one year through five years, Amortized Cost	174,204
Due after five years through ten years, Amortized Cost	98,548
Due after ten years, Amortized Cost	37,462
Debt Maturities, Amortized Cost	414,555
Due in one year or less, Fair Value	64,783
Due after one year through five years, Fair Value	175,424
Due after five years through ten years, Fair Value	98,875
Due after ten years, Fair Value	36,885
Debt Securities, Fair Value	415,533	410,095
Mortgage Backed [Member]
Schedule of Investments [Line Items]
Debt Maturities, Amortized Cost	39,769
Debt Securities, Fair Value	$ 39,566	$ 27,737