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Fair Value Measurements - Reconciliation of Liabilities Using Level 3 Inputs (Details) - USD ($) $ in Millions | 3 Months Ended |
--- | --- | ---
Mar. 31, 2018 | Mar. 31, 2017 | Dec. 31, 2017
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |
Accrued expenses (current liabilities) | $ 9.5 | $ 4.9 |
Fair Value, Measurements, Recurring |  |  |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |
Loan notes issued by variable interest entities, at fair value (included within accrued expenses and other payables) | (7.6) |  | $ (42.4)
Level 3 | Fair Value, Measurements, Recurring |  |  |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |
Loan notes issued by variable interest entities, at fair value (included within accrued expenses and other payables) | (7.6) |  | $ (42.4)
Level 3 | Fair Value, Measurements, Recurring | Silverton 2016 |  |  |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |
Beginning balance |  | 223.4 |
Distributed to third party |  | (111.2) |
Total change in fair value included in the statement of operations |  | 2.9 |
Ending balance |  | 115.1 |
Level 3 | Fair Value, Measurements, Recurring | Silverton 2017 |  |  |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |
Beginning balance | 86.6 |  |
Distributed to third party | (45.8) |  |
Total change in fair value included in the statement of operations | (1.0) |  |
Ending balance | 39.8 |  |
Third party |  |  |
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |
Accrued expenses (current liabilities) | $ 7.6 | $ 4.9 |

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- Definition Amount of increase (decrease) of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258 + Details
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