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Fair Value Measurements - Schedule of Fair Value of Financial Assets and Liabilities (Detail) - USD ($) $ in Millions		Jun. 30, 2019	Jun. 30, 2018
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets and liability		$ 104.5	$ 101.2
Money Market Funds [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets	[1]	17.2	12.5
Corporate Bonds and Notes [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets		66.9	53.3
Municipal Bonds [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets		15.4	29.2
Federal Agency Issues [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets		9.0	12.4
US Government Securities [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets		9.8	8.3
Contingent Consideration [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial liability		(13.8)	(14.5)
Level 1 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets and liability		19.7	15.3
Level 1 [Member] | Money Market Funds [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets	[1]	17.2	12.5
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	2.8
Level 2 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets and liability		98.6	100.4
Level 2 [Member] | Corporate Bonds and Notes [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets		64.4	50.5
Level 2 [Member] | Municipal Bonds [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets		15.4	29.2
Level 2 [Member] | Federal Agency Issues [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets		9.0	12.4
Level 2 [Member] | US Government Securities [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets		9.8	8.3
Level 3 [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial assets and liability		(13.8)	(14.5)
Level 3 [Member] | Contingent Consideration [Member]
Fair Value, Option, Qualitative Disclosures Related to Election [Line Items]
Total fair value of financial liability		$ (13.8)	$ (14.5)
[1] Money market funds are primarily comprised of exchange traded funds and accrued interest

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+ 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)
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-Paragraph 2
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