Business Segments, Concentration of Business, and Credit Risk and Significant Customers (Details 3) (USD $) In Thousands, unless otherwise specified					3 Months Ended												3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013 tannery	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2014 International Net Sales	Mar. 31, 2014 Net Trade Accounts Receivable	Mar. 31, 2014 Net Trade Accounts Receivable Customer One	Dec. 31, 2013 Net Trade Accounts Receivable Customer One	Mar. 31, 2014 Net Trade Accounts Receivable Customer Two	Dec. 31, 2013 Net Trade Accounts Receivable Customer Two	Mar. 31, 2014 US	Dec. 31, 2013 US	Mar. 31, 2014 All other countries		Dec. 31, 2013 All other countries		Mar. 31, 2014 All other countries International Net Sales	Mar. 31, 2013 All other countries International Net Sales
Business segment information
Property and equipment, by major country	$ 184,570	$ 174,066									$ 148,178	$ 136,726	$ 36,392	[1]	$ 37,340	[1]
Concentration risk benchmark (as a percent)					10.00%	10.00%
Concentration risk (as a percent)							11.80%	11.40%	11.40%	19.70%							32.70%	30.70%
Number of Tanneries		2
Cash and cash equivalents
Money market fund accounts	143,816	154,105
Cash	101,272	83,020
Total cash and cash equivalents	$ 245,088	$ 237,125	$ 64,591	$ 110,247

[1] No other country’s long-lived assets comprised more than 10% of total long-lived assets as of March 31, 2014 and December 31, 2013.