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Fair Value Measurements Narrative (Details) - USD ($) $ in Thousands | Dec. 31, 2017 | Dec. 31, 2016
--- | --- | ---
Cash and cash equivalents | $ 316,264 | $ 104,839
Money Market Funds [Member] |  |
Cash and cash equivalents | $ 309,100 | $ 96,700

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- Definition Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, 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. + References No definition available. + Details
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Balance Type: | debit
Period Type: | instant

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- Details
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Balance Type: |
Period Type: |