Available for Sale Marketable Debt Securities (Summary Amortized Cost and Estimated Fair Value) (Details) (Corporate Bonds [Member], USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	$ 2,508	$ 3,522
Unrealized Gain	9	19
Unrealized (Loss)	0	0
Estimated Fair Value	$ 2,517	$ 3,541