Marketable Securities, Available-for-sale (Details 2) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Contractual maturity:
Marketable securities, available-for-sale	$ 310,638	$ 347,016
Total debt securities
Contractual maturity:
Maturing in one year or less	72,766	167,413
Maturing after one year through three years	167,880	120,952
Maturing after three years	23,493	32,876
Marketable securities, available-for-sale	264,139	321,241
Time deposits and short-term pooled investments
Contractual maturity:
Marketable securities, available-for-sale	$ 46,499	$ 25,775

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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+ Details