Investments (Schedule of Amortized Cost and Estimated Fair Value of Debt Securities) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost, Due in one year or less	$ 71,490
Amortized Cost, Due after one year through five years	162,203
Amortized Cost, Due after five years through ten years	107,915
Amortized Cost, Amortized Cost Due after ten years	39,235
Debt Maturities, Amortized Cost	408,627
Fair Value, Due in one year or less	71,969
Fair Value, Due after one year through five years	163,006
Fair Value, Due after five years through ten years	108,761
Fair Value, Due after ten years	38,622
Debt securities	410,095	401,435
Collateralized Mortgage Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Debt Maturities, Amortized Cost	27,784
Debt securities	$ 27,737	$ 9,724