Investment in Securities (Schedule of Amortized Cost and Fair Value of Investment Securities) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Investment in Securities [Abstract]
Amortized Cost, Due in 1 year or less	$ 28,278
Amortized Cost, Due after 1 year through 5 years	76,717
Amortized Cost, Due after 5 years through 10 years	143,710
Amortized Cost, Due after 10 years	77,659
Amortized Cost, Total	326,364
Fair Value, Due in 1 year or less	28,636
Fair Value, Due after 1 year through 5 years	80,844
Fair Value, Due after 5 years through 10 years	149,285
Fair Value, Due after 10 years	81,075
Fair Value, Total	$ 339,840	$ 317,767