Credit Agreement (Details) In Thousands, unless otherwise specified	1 Months Ended	6 Months Ended
	Jun. 30, 2013 Credit Agreement USD ($)	Jun. 30, 2013 Credit Agreement Subsequent to June 30, 2013 USD ($)	Jun. 30, 2013 China Credit Agreement Subsequent to June 30, 2013 USD ($)	Jun. 30, 2013 China Credit Agreement Subsequent to June 30, 2013 CNY
Notes Payable and Long-Term Debt
Additional borrowing related to headquarters allowed under Credit Agreement covenants prior to amendment	$ 75,000
Additional borrowing related to headquarters allowed under Credit Agreement covenants	80,000
Outstanding borrowings	26,000	182,000
Weighted average interest rate (as a percent)	3.75%
Outstanding letters of credit	189
Amount unused balance under the Credit Agreement	373,811
Current borrowing capacity	220,795
Amount borrowed	12,500	156,000
Amount allowed to be borrowed in the third and fourth quarters			10,000	60,000
Amount allowed to be borrowed in the first and second quarters			$ 3,300	20,000
Percentage of facility amount in USD guaranteed			110.00%	110.00%