Common Stock Repurchase Program - Additional Information (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	9 Months Ended			1 Months Ended
	Sep. 30, 2013	Sep. 30, 2013 Additional Paid-in Capital	Sep. 30, 2013 Retained Earnings	Oct. 27, 2011 Common Stock Repurchase Program
Share Repurchases [Line Items]
Repurchase of common stock, common stock authorized				$ 150.0
Repurchase of common stock, shares repurchased	2.7
Repurchase of common stock, average price per share	$ 34.95
Repurchase of common stock, aggregate purchase price	$ 95.1	$ 24.5	$ 70.6