Earnings Per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jul. 01, 2012	Jun. 26, 2011	Jul. 01, 2012	Jun. 26, 2011
Earnings Per Share (Thousands of Dollars and Shares Except Per Share Data) [Abstract]
Net earnings (in dollars)	$ 43,427	$ 58,051	$ 40,848	$ 75,247
Basic [Abstract]
Average shares outstanding (in shares)	130,294	136,073	129,918	136,859
Equivalent shares (basic) (in shares)	130,294	136,073	129,918	136,859
Net earnings per common share-basic (in dollars per share)	$ 0.33	$ 0.43	$ 0.31	$ 0.55
Diluted [Abstract]
Average shares outstanding (in shares)	130,294	136,073	129,918	136,859
Effect of dilutive securities:
Options and other share-based awards (in shares)	1,824	3,168	1,907	3,238
Equivalent shares (diluted) (in shares)	132,118	139,241	131,825	140,097
Net earnings per common share-diluted (in dollars per share)	$ 0.33	$ 0.42	$ 0.31	$ 0.54
Options to acquire shares totaling excluded as antidilutive	3,504	1,157	3,523	1,165