Consolidated Statements Of Stockholders' Equity (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 25, 2010	Dec. 26, 2009
Consolidated Statements Of Stockholders' Equity [Abstract]
Cash dividends, per share	$ 0.53	$ 0.46	$ 0.41
Contribution of shares to retirement plans, shares	12,508	14,363	15,013
Acquired shares from stockholders, shares	23,513	23,731	37,895
Sale of shares to stockholders, shares	9,711	9,771	9,482
Retirement of shares, shares	14,278	14,820	16,929