Certain Balance Sheet Components Depreciation Expense (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Depreciation expense [Line Items]
Depreciation expense	$ 15,656	$ 16,607	$ 45,989	$ 49,112