Accrued Liabilities (Schedule of Accrued Liabilities) (Details) (USD $) In Thousands	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2009
Accrued Liabilities
Salaries, wages and related fringe benefits	$ 57,751		$ 50,540
Taxes	32,977		25,367
Advance payments on sales contracts	43,689		39,026
Product warranty	23,531	21,033	19,100	17,006	18,134	19,312
Other	45,741		45,008
Total accrued liabilities	$ 203,689		$ 179,041