Benefit Plans (Details 2) (USD $) In Thousands, except Per Share data	6 Months Ended
	Jul. 01, 2011
Stock option activity under the plans
Balance at December 31, 2010, Stock Options Outstanding	11,020
Balance at December 31, 2010, Weighted Average Exercise Price	$ 6.90
Options granted, Stock Options Outstanding	833
Options granted, Weighted Average Exercise Price	$ 9.63
Options exercised, Stock Options Outstanding	(1,714)
Options exercised, Weighted Average Exercise Price	$ 6.33
Options cancelled, Stock Options Outstanding	(507)
Options cancelled, Weighted Average Exercise Price	$ 7.55
Options expired, Stock Options Outstanding	(384)
Options expired, Weighted Average Exercise Price	$ 9.11
Balance at July 1, 2011, Stock Options Outstanding	9,248
Balance at July 1, 2011, Weighted Average Exercise Price	$ 7.12
Options Vested and exercisable as of July 1, 2011, Stock Options Outstanding	6,492
Options vested and expected-to-vest as of July 1, 2011, Stock Options Outstanding	9,122