Balance Sheet Information (Details 2) (USD $)	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010
Restricted Cash
Restricted cash	$ 54,484,000		$ 76,115,000
Accounts Receivable, net
Allowance for doubtful accounts receivable (in dollars)	500,000		500,000
Inventories
Raw materials	54,127,000		49,953,000
Work in process	28,315,000		33,181,000
Finished goods	30,897,000		25,353,000
Inventories	113,339,000		108,487,000
Goodwill
Balance at the beginning of the period	52,003,000	52,003,000
Business Acquired	15,104,000
Balance at the end of the period	67,107,000
Accrued Warranty
Balance as of the beginning of year	9,238,000	6,675,000
Warranties issued during the year	5,843,000	5,085,000
Settlements made during the year	(4,489,000)	(3,241,000)
Balance as of the end of year	10,592,000	8,519,000
Metrology Segment Disposal
Restricted Cash
Restricted cash	22,900,000
Restriction period on use of proceeds which are held in escrow (in years)	1
Collateral for Bank Guarantees
Restricted Cash
Restricted cash	$ 31,600,000