Balance Sheet Information (Details 2) (USD $)	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2010 Metrology Segment Disposal Y	Oct. 07, 2010 Metrology Segment Disposal Y	Dec. 31, 2011 Collateral for Bank Guarantees	Dec. 31, 2010 Collateral for Bank Guarantees
Restricted Cash
Restricted cash	$ 577,000	$ 76,115,000	$ 22,900,000	$ 22,900,000	$ 600,000	$ 53,200,000
Restriction period on use of proceeds which are held in escrow (in years)			1	1
Accounts Receivable, net
Allowance for doubtful accounts receivable (in dollars)	500,000	500,000
Inventories
Raw materials	57,169,000	49,953,000
Work in process	20,118,000	33,181,000
Finished goods	36,147,000	25,353,000
Inventories	$ 113,434,000	$ 108,487,000