Investments (Amortized Cost and Estimated Fair Values of Debt Securities Held-To-Maturity by Contractual Maturity) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Amortized Cost
Due in one year or less	$ 3,099	$ 1,720
Due after one year through five years	4,563	3,249
Due after five years through ten years	154,865	139,033
Due after ten years	59,163	80,636
Total debt securities held-to-maturity	221,690	224,638
Estimated Fair Value
Due in one year or less	3,112	1,725
Due after one year through five years	4,618	3,269
Due after five years through ten years	163,345	135,074
Due after ten years	52,055	75,939
Total debt securities held-to-maturity	$ 223,130	$ 216,007