Segment Reporting - Geographic Schedul of Revenue and Long-lived Assets (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Revenues from External Customers and Long-Lived Assets [Line Items]
Net Sales	$ 274,021	$ 304,039	$ 329,392	$ 362,916	$ 282,150	$ 294,860	$ 282,568	$ 272,788	$ 1,270,368	$ 1,132,366	$ 943,706
Long-lived assets	79,640				82,141				79,640	82,141
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Net Sales									988,161	895,165	757,052
Long-lived assets	68,253				72,138				68,253	72,138
All other countries
Revenues from External Customers and Long-Lived Assets [Line Items]
Net Sales									282,207	237,201	186,654
Long-lived assets	$ 11,387				$ 10,003				$ 11,387	$ 10,003