Cash, Cash Equivalents, Available for Sale Securities and Restricted Cash (Available for Sale Securities) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Cost	$ 0	$ 50,865
Available for sale securities	0	50,875
Unrealized Gain	0	10
US Government Agency Notes [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	0	7,093
Available for sale securities	0	7,097
Unrealized Gain	0	4
US Treasury Notes [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	0	0
Available for sale securities	0	0
Unrealized Gain	0	0
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	0	43,772
Available for sale securities	0	43,778
Unrealized Gain	$ 0	$ 6