Accounting for Stock-Based Compensation (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended				1 Months Ended
	Nov. 30, 2013 Stock options	Nov. 30, 2012 Stock options	Nov. 30, 2013 Stock options	Nov. 30, 2012 Stock options	Nov. 30, 2013 Restricted stock	Nov. 30, 2012 Restricted stock	Nov. 30, 2013 Restricted stock	Nov. 30, 2012 Restricted stock	Nov. 30, 2013 Performance-based restricted stock	Nov. 30, 2013 Time-based restricted stock	Jun. 30, 2013 Time-based restricted stock Board of Directors
Share-Based Compensation
Granted (in shares)			1,027,515
Granted (in dollars per share)			$ 25.43
Weighted average fair value of stock options granted (in dollars per share)			$ 10.24
Assumptions used in the Black-Scholes option pricing models to estimate the fair value of each stock option grant
Risk-free interest rate (as a percent)			1.40%
Expected volatility of common stock (as a percent)			49.10%
Dividend yield (as a percent)			1.20%
Expected option term			5 years 2 months 12 days
Stock options, additional disclosures
Total intrinsic value of stock options exercised			$ 3.7	$ 0.1
Compensation expense	$ 1.0	$ 0.9	$ 1.5	$ 1.6	$ 1.4	$ 0.9	$ 2.5	$ 3.1
Granted (in shares)									60,808	60,808	45,000
Granted (in dollars per share)									$ 25.43	$ 25.43	$ 20.68