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Investments - Investments Classified as Long-Term Available-for-Sale Investments and Long-Term Cost Method Investments (Detail) - USD ($) $ in Thousands | Sep. 30, 2018 | Dec. 31, 2017
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Schedule of Available-for-sale Securities and Cost-method Investments [Line Items] |  |
Investments classified as long-term | $ 10,404 | $ 10,655
Group Insurance Contracts [Member] |  |
Schedule of Available-for-sale Securities and Cost-method Investments [Line Items] |  |
Investments classified as long-term | 6,004 | 6,255
Minority Interest in Private Company [Member] |  |
Schedule of Available-for-sale Securities and Cost-method Investments [Line Items] |  |
Investments classified as long-term | $ 4,400 | $ 4,400

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- Definition Schedule of available-for-sale securities and cost-method investments. + References No definition available. + Details
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- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in net income (available-for-sale), classified as noncurrent. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=109979856&loc=d3e26626-111562 + Details
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- Definition Amount of investment in equity security without readily determinable fair value. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 321 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=84241550&loc=SL75117539-209714 + Details
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