Summary of Significant Accounting Policies - Shipping and Handling Expenses (Details) (Selling, General and Administrative Expenses [Member], USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Selling, General and Administrative Expenses [Member]
Shipping and Handling Costs [Line Items]
Shipping and Handling Costs	$ 4.1	$ 4.1	$ 4.0