Fair Value Measurements - Changes in Fair Value of Contingent Consideration (Details) $ in Millions	3 Months Ended
Dec. 31, 2016 USD ($)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Contingent consideration as of September 30, 2016	$ 118.4
Change in fair value of contingent consideration	10.6
Contingent consideration as of December 31, 2016	129.0
TRA
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Contingent consideration as of September 30, 2016	83.4
Change in fair value of contingent consideration	2.7
Contingent consideration as of December 31, 2016	86.1
Deferred Cash Consideration
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Contingent consideration as of September 30, 2016	35.0
Change in fair value of contingent consideration	7.9
Contingent consideration as of December 31, 2016	$ 42.9

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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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

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- Definition

Fair value 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

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