Stockholders' Equity (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Stock Repurchase Program
Total Shares Purchased	3,300,000	3,400,000	100,000
Shares Remaining Under Board Authorization	3,900,000
Shares Repurchased Under Board Authorization	2,974,200	3,151,828
Total cost (in dollars)	$ 38.9	$ 50.3
Average share price (in dollars per share)	$ 13.09	$ 15.95
Shares repurchased to satisfy minimum statutory withholding tax upon the net settlement of equity awards	369,099	235,075	119,801
July 2008
Stock Repurchase Program
Amount Authorized by Board (in shares)	4,000,000
Total Shares Purchased	4,000,000
Shares Repurchased Under Board Authorization		2,100,000
July 2010
Stock Repurchase Program
Amount Authorized by Board (in shares)	4,000,000
Total Shares Purchased	4,000,000
Shares Repurchased Under Board Authorization	2,900,000	1,100,000
October 2011
Stock Repurchase Program
Amount Authorized by Board (in shares)	4,000,000
Total Shares Purchased	100,000
Shares Remaining Under Board Authorization	3,900,000
Shares Repurchased Under Board Authorization	100,000