Summary of Significant Accounting Policies (Details 7) (Fair value measured on recurring basis, USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Total Carrying Value
Assets and liabilities carried at fair value measured on a recurring basis
Money market funds	$ 72,942	$ 68,800
Time deposits	6,418	149,829
Trading securities	12,156	11,071
Derivative assets	85
Derivative liabilities	7,059	1,522
Quoted prices in active markets (Level 1)
Assets and liabilities carried at fair value measured on a recurring basis
Trading securities	11,568	10,525
Significant other observable inputs (Level 2)
Assets and liabilities carried at fair value measured on a recurring basis
Money market funds	72,942	68,800
Time deposits	6,418	149,829
Trading securities	588	546
Derivative assets	85
Derivative liabilities	$ 7,059	$ 1,522

- Definition

Any certificate of deposit or savings account held by a bank or other financial institution for a short-term specified period of time. Because of their short-term, time deposits are considered highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months.

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