Summary of Significant Accounting Policies (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Accounting Policies [Abstract]
Product return period	30 days
Cash	$ 186,300,000	$ 121,200,000
Cash equivalents	58,800,000	58,700,000
Advertising expense	$ 69,938,000	$ 54,112,000	$ 30,651,000