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Fair Value Measurements - Schedule of Fair Value of Financial Assets (Detail) - USD ($) $ in Millions		Jun. 30, 2017	Jun. 30, 2016
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets and liability		$ (24.8)	$ 162.4
Money Market Funds [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets	[1]	7.4	2.4
Corporate Bonds and Notes [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets		50.4	51.0
Municipal Bonds [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets		36.9	85.6
Federal Agency Issues [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets		13.8	25.5
US Government Securities [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets		7.2	8.3
Contingent Consideration [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial liability		(140.5)	(10.4)
Level 1 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets and liability		7.4	2.4
Level 1 [Member] | Money Market Funds [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets	[1]	7.4	2.4
Level 2 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets and liability		108.3	170.4
Level 2 [Member] | Corporate Bonds and Notes [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets		50.4	51.0
Level 2 [Member] | Municipal Bonds [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets		36.9	85.6
Level 2 [Member] | Federal Agency Issues [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets		13.8	25.5
Level 2 [Member] | US Government Securities [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets		7.2	8.3
Level 3 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets and liability		(140.5)	(10.4)
Level 3 [Member] | Contingent Consideration [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial liability		$ (140.5)	$ (10.4)
[1] Money market funds are primarily comprised of exchange traded funds and accrued interest

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- Definition

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

+ 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 (a)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

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+ References

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- Definition

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- Definition

Fair value of financial and nonfinancial obligations.

+ 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 (a)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

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