Financial Instruments (Contractual Maturities) (Details 3) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Financial Instruments Contractual Maturities Details 3
Due within one year, amortized cost	$ 106,268	$ 65,637
Due after one year through five years, amortized cost	25,074	17,629
Due after five years through ten years, amortized cost	0	0
Due after ten years, amortized cost	0	0
Due within one year, fair value	65,637	65,632
Due after one year through five years, fair value	17,629	17,612
Due after five years through ten years, fair value	0
Due after ten years, fair value	0
Total debt securities, amortized cost	131,342	83,266
Total debt securities, fair value	$ 131,334	$ 83,244