Marketable Securities (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014 Municipal auction rate securities	Jun. 30, 2013 Municipal auction rate securities
Summary of marketable securities
Available-for-sale securities, Cost - Non-current			$ 5.9	$ 5.9
Available-for-sale securities, Unrealized Losses - Non-current			(0.4)	(0.5)
Available-for-sale securities, Estimated Fair Value - Non-current			5.5	5.4
Proceeds from sales and maturities of marketable securities	$ 0	$ 0