Investments Investments (Investments Held to Maturity) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Gain (Loss) on Investments [Line Items]
Amortized Cost	$ 18,828	$ 10,873
Gross Unrealized Gain	3	0
Gross Unrealized (Loss)	(59)	(10)
Fair Value	18,772	10,863
Current Assets [Member]
Gain (Loss) on Investments [Line Items]
Amortized Cost	7,353	2,832
Gross Unrealized Gain	3	0
Gross Unrealized (Loss)	0	(1)
Fair Value	7,356	2,831
Non Current Assets [Member]
Gain (Loss) on Investments [Line Items]
Amortized Cost	11,475	8,041
Gross Unrealized Gain	0	0
Gross Unrealized (Loss)	(59)	(9)
Fair Value	$ 11,416	$ 8,032