Stockholders' Equity (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Stock Repurchase Program
Shares Repurchased Under Board Authorization	2,470,000	2,974,200	3,151,828
Total cost (in dollars)	$ 23.5	$ 38.9	$ 50.3
Average share price (in dollars per share)	$ 9.50	$ 13.09	$ 15.95
Shares repurchased to satisfy minimum statutory withholding tax upon the net settlement of equity awards	270,467	369,099	235,075
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	2,600,000
Shares Remaining Under Board Authorization	1,500,000
Shares Repurchased Under Board Authorization	2,500,000	100,000