Stockholders' Equity (Details) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended	12 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Apr. 23, 2014	Apr. 23, 2013
Stockholders' Equity
Approved stock repurchase program, authorized amount			$ 200	$ 150
Repurchase of common stock (in shares)	1,050,715	3,110,114
Repurchase of common stock, amount	45.0	121.8
Remaining capacity under the stock repurchase program	$ 130.1		$ 37.5