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Significant Accounting Policies Investments (Details) - USD ($) $ in Millions | Dec. 31, 2018 | Dec. 31, 2017
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Significant Accounting Policies [Abstract] |  |
Debt Securities, Held-to-maturity | $ 1.5 | $ 1.4

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- Definition Significant Accounting Policies [Abstract] + References No definition available. + Details
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- Definition Amount of investment in debt security measured at amortized cost (held-to-maturity). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109979856&loc=d3e26610-111562 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27232-111563 + Details
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