Summary of Significant Accounting Policies Consolidated Statement of Cash Flow Restatement (Details) (USD $) In Thousands	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010
Net income	$ 61,556	$ 50,561
Deferred taxes, net	(6,081)	8,132
Accounts receivable	12,106	52,124
Unearned revenue	24,159	2,365
Warranty	9,510	14,355
As previously reported [Member]
Net income		53,687
Deferred taxes, net		(7,159)
Accounts receivable		(52,332)
Unearned revenue		(1,205)
Warranty		14,034
As restated [Member]
Net income		50,561
Deferred taxes, net		(8,132)
Accounts receivable		(52,124)
Unearned revenue		2,365
Warranty		$ 14,355