Product Warranties (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended			6 Months Ended
	Jun. 30, 2013	Mar. 31, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Product Liability Contingency [Line Items]
Maximum product warranty term				3 years
Warranty accrual	$ 2,683	$ 2,743	$ 4,779	$ 2,683	$ 4,779
Movement in Standard Product Warranty Accrual [Roll Forward]
Balance, beginning of period	2,743	4,455	6,930	4,455	6,871
Charges to operations	372		106	490	474
Deductions for costs incurred	(145)		(2,199)	(1,166)	(2,508)
Changes in estimates	(287)	(809)	(58)	(1,096)	(58)
Balance, end of period	$ 2,683	$ 2,743	$ 4,779	$ 2,683	$ 4,779