Guarantees (Tables)

6 Months Ended

Jun. 30, 2012

Guarantees [Abstract]

Changes in accrued warranty

	Three Months Ended						Six Months Ended
	June 30, 2012			June 25, 2011			June 30, 2012			June 25, 2011
Balance at beginning of period	$	6,727		$	6,303		$	6,801		$	5,016
Warranty expense accruals		1,148			2,178			2,813			5,449
Warranty payments		(1,741	)		(2,401	)		(3,480	)		(4,385	)
Balance at end of period	$	6,134		$	6,080		$	6,134		$	6,080