Stock Repurchases (Details) (Stock repurchase program, August 25, 2011 [Member], USD $) In Millions, except Share data, unless otherwise specified	0 Months Ended	1 Months Ended	3 Months Ended
	Aug. 25, 2011 months	Oct. 01, 2011	Dec. 31, 2011
Stock repurchase program, August 25, 2011 [Member]
Equity, Class of Treasury Stock [Line Items]
Authorized repurchase of common stock	$ 50.0
Period of repurchase program from the date of authorization (in months)	12
Remaining authorized repurchase amount		25.0	4.3
Number of shares of outstanding common stock repurchased and retired			450,500
Average price per share of outstanding common stock repurchased and retired			$ 45.84
Total amount of outstanding common stock repurchased and retired, excluding expenses			$ 20.7