Stock-Based Compensation (Stock Option Activity Under the Principal Option Plans) (Details) (Stock Options [Member], USD $) In Thousands, except Share data, unless otherwise specified	6 Months Ended
	Jun. 26, 2011
Stock Options [Member]
Number of Shares, Outstanding at beginning of period	2,745,796
Number of Shares, Granted	93,144
Number of Shares, Exercised	(124,098)
Number of Shares, Forfeited or expired	(18,965)
Number of Shares, Outstanding at end of period	2,695,877
Number of Shares, Vested and expected to vest	2,653,406
Number of Shares, Exercisable	2,187,179
Weighted-Average Exercise Price, Outstanding at beginning of period	$ 19.11
Weighted-Average Exercise Price, Granted	$ 21.91
Weighted-Average Exercise Price, Exercised	$ 12.50
Weighted-Average Exercise Price, Forfeited or expired	$ 17.44
Weighted-Average Exercise Price, Outstanding at end of period	$ 19.52
Weighted-Average Exercise Price, Vested and expected to vest	$ 19.52
Weighted-Average Exercise Price, Exercisable	$ 19.66
Weighted-Average Remaining Contractual Term, Outstanding at beginning of period in years	5.320
Weighted-Average Remaining Contractual Term, Outstanding at end of period in years	5.030
Weighted-Average Remaining Contractual Term, Vested and expected to vest in years	4.970
Weighted-Average Remaining Contractual Term, Exercisable in years	4.390
Aggregate Intrinsic Value, Outstanding at beginning of period	$ 8,731
Aggregate Intrinsic Value, Outstanding at end of period	3,571
Aggregate Intrinsic Value, Vested and expected to vest	3,533
Aggregate Intrinsic Value, Exercisable	$ 2,722