Stockholders' Equity (Details) (USD $) In Millions, except Share data, unless otherwise specified	1 Months Ended		3 Months Ended	6 Months Ended	69 Months Ended
	Sep. 30, 2012	Oct. 31, 2008	Jun. 30, 2014	Jun. 30, 2014	Jun. 30, 2014
Stockholders' Equity
Increase in maximum amount approved under common stock repurchase program	$ 10
Maximum amount authorized under the common stock repurchase program		10
Shares of common stock repurchased			42,866		2,888,581
Aggregate cost of shares of common stock repurchased			0.4	0.4	14.7
Available authorized repurchase amount				$ 5.3