Current Liabilities Warranty Schedule (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Accrued Liabilities, Current [Abstract]
Balance as of January 1	$ 18,252	$ 21,506
Warranties provided during the period	11,225	5,996
Settlements made during the period	(12,068)	(9,681)
Changes in liability for pre-existing warranties during the period, including expirations	2,433	431
Balance as of December 31	$ 19,842	$ 18,252