Financial Instruments (Contractual Maturities) (Details 3) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Financial Instruments Contractual Maturities Details 3
Due within one year, amortized cost	$ 95,499	$ 103,280
Due after one year through five years, amortized cost	3,201	26,005
Due after five years through ten years, amortized cost	0	0
Due within one year, fair value	95,430	103,266
Due after one year through five years, fair value	3,196	26,004
Due after five years through ten years, fair value	0	0
Total debt securities, amortized cost	98,700	129,285
Total debt securities, fair value	$ 98,626	$ 129,270