Investment in Securities (Schedule of Amortized Cost and Fair Value of Investment Securities) (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Investment in Securities [Abstract]
Amortized Cost, Due in 1 year or less	$ 23,893
Amortized Cost, Due after 1 year through 5 years	88,356
Amortized Cost, Due after 5 years through 10 years	130,452
Amortized Cost, Due after 10 years	96,463
Amortized Cost, Total	339,164
Fair Value, Due in 1 year or less	24,055
Fair Value, Due after 1 year through 5 years	92,275
Fair Value, Due after 5 years through 10 years	134,615
Fair Value, Due after 10 years	96,875
Fair Value, Total	$ 347,820	$ 356,141