Stock-Based Compensation - Additional Disclosures (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	9 Months Ended
Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2017	Mar. 31, 2016
Restricted Stock Units
Stock-based compensation, additional disclosures
Weighted average grant-date fair value of RSUs granted	$ 54.95	$ 31.97	$ 45.98	$ 41.91
Total fair value of shares vested from RSU grants	$ 4.5	$ 3.6	$ 12.8	$ 9.8
Total unrecognized compensation cost	$ 28.2		$ 28.2
Total unrecognized compensation cost, period of recognition			2 years 8 months 29 days
Excess tax benefits from stock-based compensation			$ 4.4	$ 3.4
Stock Options
Stock-based compensation, additional disclosures
Weighted average fair value (in dollars per share)	$ 13.70	$ 10.47	$ 12.96	$ 13.19
Total unrecognized compensation cost	$ 7.5		$ 7.5
Total unrecognized compensation cost, period of recognition			2 years 8 months 8 days
Total intrinsic value of options exercised	$ 2.9	$ 0.3	$ 6.9	$ 2.6
Cash proceeds from option exercises			$ 7.9	$ 2.9
2010 Plan
Stock-based compensation, additional disclosures
Common stock reserved for future issuance or settlement (in shares)	10,848,882		10,848,882

Amount of increase in additional paid in capital (APIC) resulting from a tax benefit associated with share-based compensation plan other than an employee stock ownership plan (ESOP). Includes, but is not limited to, excess tax benefit.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 740
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=65880886&loc=d3e23524-113945

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

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-Name Accounting Standards Codification
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Aggregate number of common shares reserved for future issuance.

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Aggregate proceeds received by the entity during the annual period from exercises of stock or unit options and conversion of similar instruments granted under equity-based payment arrangements.

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-Publisher FASB
-Name Accounting Standards Codification
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Unrecognized cost of unvested share-based compensation awards.

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Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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