Investments (Amortized Cost and Aggregate Fair Value of Debt Securities, by Contractual Maturity) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Investments [Abstract]
Available-for-sale Securities, Due in one year or less, Amortized Cost	$ 1,582
Available-for-sale Securities, Due in one year or less, Fair Value	1,615
Available-for-sale Securities, Due after one year through five years, Amortized Cost	15,047
Available-for-sale Securities, Due after one year through five years, Fair Value	15,006
Available-for-sale Securities, Due after five years through ten years, Amortized Cost	34,497
Available-for-sale Securities, Due after five years through ten years, Fair Value	34,444
Available-for-sale Securities, Due after ten years, Amortized Cost	41,711
Available-for-sale Securities, Due after ten years, Fair Value	41,727
Available-for-sale securities, Amortized Cost	92,837	$ 92,077
Available-for-sale Securities, Fair Value	92,792
Held-to-maturity Securities, Due in one year or less, Amortized Cost	4
Held-to-maturity Securities, Due in one year or less, Fair Value	4
Held-to-maturity Securities, Due after one year through five years, Amortized Cost	26
Held-to-maturity Securities, Due after one year through five years, Fair Value	27
Held-to-maturity Securities, Due after five years through ten years, Amortized Cost	80
Held-to-maturity Securities, Due after five years through ten years, Fair Value	87
Held-to-maturity Securities, Due after ten years, Amortized Cost	1,780
Held-to-maturity Securities, Due after ten years, Fair Value	1,812
Held-to-maturity Securities, Amortized Cost	1,890	2,439
Held-to-maturity Securities, Fair Value	$ 1,930	$ 2,504