Fair Value Measurements (Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents at fair value	$ 86,584	$ 64,793
Total Assets	86,584	64,793
IDSI acquisition short-term note		(945)
Total current maturities of other long-term debt		(945)
Derivatives	(47)
Total other accrued liabilities	(47)
Total Liabilities	(47)	(945)
Domestic money market funds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents at fair value	58,192	42,273
Non domestic bank certificates of deposit [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents at fair value	28,392	22,520
Fair Value, Inputs, Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents at fair value	86,584	64,793
Total Assets	86,584	64,793
Fair Value, Inputs, Level 1 [Member] | Domestic money market funds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents at fair value	58,192	42,273
Fair Value, Inputs, Level 1 [Member] | Non domestic bank certificates of deposit [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash equivalents at fair value	28,392	22,520
Fair Value, Inputs, Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
IDSI acquisition short-term note		(945)
Total current maturities of other long-term debt		(945)
Derivatives	(47)
Total other accrued liabilities	(47)
Total Liabilities	$ (47)	$ (945)