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Equity-Based Compensation (Management Stock Purchase Plan) (Details) - Management Stock Purchase Plan - USD ($) | 9 Months Ended
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Sep. 30, 2018 | Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Share-based liabilities paid (in thousands) | $ 4,986,000 | $ 2,392,000
Restricted stock units |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Restricted stock units credited | $ 74,180 | $ 90,754

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- Definition Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (d)(2) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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