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Investments (Narrative) (Details) - USD ($) | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2018 | Mar. 31, 2017 | Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |
Equity investment losses were considered to be other than temporary | $ 0 | $ 0 |
Technology investments in non-consolidated affiliates (less than) |  |  | 20.00%
Technology investments in non-consolidated affiliates | 3,200,000 |  |
Accounting Standards Update 2016-01 |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |
Cumulative-effect adjustment | $ 6,600,000 |  |

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- Definition Amount, after adjustment, of cost-method investment. Adjustments include, but are not limited to, dividends received in excess of earnings after date of investment that are considered a return of investment and other than temporary impairments. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.12) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 325 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=75025870&loc=d3e40691-111596 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 325 -SubTopic 20 -Section 35 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=75027002&loc=d3e40346-111594 + Details
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