Certain Balance Sheet Components Accounts Receivable, Net Additional Information (Details) (USD $)	9 Months Ended
	Sep. 30, 2011	Dec. 31, 2010
Long term Retainage Contract Receivables [Line Items]
Unbilled Contracts Receivable	$ 5,800,000	$ 2,100,000
Number of months current retainage amounts and unbilled receivables are expected to be collected	12 months
Long-term unbilled receivables and long-term retainage contract receivables	31,400,000	5,900,000
Number of months collection is not anticipated for long-term unbilled and retainage contract receivables	12 months
Number of Months Long-Term Unbilled and Retainage Contract Receivables are Expected to be Collected	18 months
Reclassified from current accounts receivables to other long-term assets [Member]
Long term Retainage Contract Receivables [Line Items]
Unbilled Contracts Receivable	7,500,000
Contract Receivable Retainage, Due after One Year	11,700,000
Long Term Retainage Contract Receivables [Member]
Long term Retainage Contract Receivables [Line Items]
Contract Receivable Retainage, Due One Year or Less	$ 887,000	$ 12,500,000