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Acquisitions Of Businesses (Details) $ in Thousands |  |  |  |  |  | 12 Months Ended |
--- | --- | --- | --- | --- | --- | --- | ---
May 03, 2018 Company | Apr. 04, 2018 Company | Nov. 01, 2017 Company | Mar. 01, 2017 Company | Jan. 04, 2017 Company | Dec. 31, 2017 USD ($) | Sep. 30, 2018 USD ($)
Business Acquisition [Line Items] |  |  |  |  |  |  |
Goodwill |  |  |  |  |  | $ 964,893 | $ 978,243
Number of businesses acquired | Company | 1 | 1 | 1 | 1 | 1 |  |
2017 Acquisitions [Member] |  |  |  |  |  |  |
Business Acquisition [Line Items] |  |  |  |  |  |  |
Purchase price |  |  |  |  |  | 111,900 |
Working capital acquired |  |  |  |  |  | 12,300 |
Other net assets |  |  |  |  |  | 2,300 |
Goodwill |  |  |  |  |  | 40,700 |
Identifiable intangible assets |  |  |  |  |  | $ 56,600 |

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- Definition Amount of intangible assets, excluding goodwill, acquired at the acquisition date. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 805 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=84161108&loc=d3e4845-128472 + Details
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- Definition Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=77989000&loc=SL49117168-202975 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 20 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=99380562&loc=d3e13770-109266 + Details
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