Business Segments, Concentration of Business, and Credit Risk and Significant Customers (Details 3) (USD $) In Thousands, unless otherwise specified										3 Months Ended		6 Months Ended
	Jun. 30, 2011	Dec. 31, 2010	Jun. 30, 2010	Jun. 30, 2011 US	Dec. 31, 2010 US	Jun. 30, 2011 UK	Dec. 31, 2010 UK	Jun. 30, 2011 All other countries	Dec. 31, 2010 All other countries	Jun. 30, 2011 International Net Sales	Jun. 30, 2010 International Net Sales	Jun. 30, 2011 International Net Sales	Jun. 30, 2010 International Net Sales	Jun. 30, 2011 Net Trade Accounts Receivable Customer One	Dec. 31, 2010 Net Trade Accounts Receivable Customer One	Dec. 31, 2010 Net Trade Accounts Receivable Customer Two	Jun. 01, 2011 Long-lived assets	Dec. 31, 2010 Long-lived assets
Long-lived assets, which consist of property and equipment, by major country
Property and equipment, by major country	$ 54,541	$ 47,737		$ 39,990	$ 36,591	$ 6,169	$ 6,753	$ 8,382	$ 4,393
Concentration risks
Concentration risk, minimum (greater than, as a percent)	10.00%		10.00%														10.00%	10.00%
Number of customers considered concentration risk														1		1
Concentration risk (as a percent)														11.50%	33.20%	10.10%
Concentration risk benchmark (as a percent)										46.30%	52.40%	35.70%	37.80%