Significant Accounting Policies Narrative (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Reserve for returns	$ 5.3	$ 1.5
Capitalized advertising	0	0.8
Advertising costs	28.0	22.3	16.5
Selling and Marketing Expense [Member]
Reclassifications from general and administrative to selling and marketing expense			$ 15.0