Stock-Based Compensation - Additional Disclosures (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2015	Dec. 31, 2014
Stock Options
Stock-based compensation, additional disclosures
Total unrecognized compensation cost	$ 6.6		$ 6.6
Total unrecognized compensation cost, period of recognition			2 years 10 months 24 days
Total intrinsic value of options exercised	$ 1.4	$ 0.7	$ 2.3	$ 3.0
Cash proceeds from option exercises			$ 2.4	$ 1.5
Restricted Stock Units
Stock-based compensation, additional disclosures
Weighted average grant-date fair value of RSUs granted	$ 38.04		$ 43.94	$ 43.44
RSUs granted (in shares)		0	347,975
Total fair value of shares vested from RSU grants	$ 2.9	$ 3.5	$ 6.3	$ 7.7
Total unrecognized compensation cost	$ 22.1		$ 22.1
Total unrecognized compensation cost, period of recognition			2 years 9 months 18 days
Excess tax benefits from stock-based compensation			$ 2.1	$ 2.7
2010 Plan
Stock-based compensation, additional disclosures
Common stock reserved for future issuance or settlement (in shares)	5,600,000		5,600,000