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Fair Value Measurements - Schedule of Fair Value of Financial Assets and Liabilities (Detail) - USD ($) $ in Millions		Dec. 31, 2019	Jun. 30, 2019
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets and liability		$ 110.3	$ 104.5
Money Market Funds [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets	[1]	12.6	17.2
Corporate Bonds and Notes [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets		67.6	66.9
Municipal Bonds [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets		20.9	15.4
Federal Agency Issues [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets		4.0	9.0
US Government Securities [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets		15.5	9.8
Contingent Consideration [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial liability		(10.3)	(13.8)
Level 1 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets and liability		12.6	19.7
Level 1 [Member] | Money Market Funds [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets	[1]	12.6	17.2
Level 1 [Member] | Corporate Bonds and Notes [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets			2.5
Level 2 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets and liability		108.0	98.6
Level 2 [Member] | Corporate Bonds and Notes [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets		67.6	64.4
Level 2 [Member] | Municipal Bonds [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets		20.9	15.4
Level 2 [Member] | Federal Agency Issues [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets		4.0	9.0
Level 2 [Member] | US Government Securities [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets		15.5	9.8
Level 3 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets and liability		(10.3)	(13.8)
Level 3 [Member] | Contingent Consideration [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial liability		$ (10.3)	$ (13.8)
[1] Money market funds are primarily comprised of exchange traded funds and accrued interest.

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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://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258

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-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
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