Marketable Securities, Available-for-sale (Details 2) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Contractual maturity:
ESTIMATED FAIR VALUE	$ 214,088	$ 313,155
Total debt securities
Contractual maturity:
Maturing in one year or less	80,094	129,384
Maturing after one year through three years	100,249	154,169
Maturing after three years	23,727	21,363
ESTIMATED FAIR VALUE	204,070	304,916
Time deposits and short-term pooled investments
Contractual maturity:
ESTIMATED FAIR VALUE	$ 10,018	$ 8,239