Periodic Financial Data (Schedule Of Periodic Financial Data) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended						4 Months Ended		12 Months Ended
	Sep. 11, 2011	Jun. 19, 2011	Mar. 27, 2011	Sep. 12, 2010	Jun. 20, 2010	Mar. 28, 2010	Jan. 01, 2012	Jan. 02, 2011	Jan. 01, 2012	Jan. 02, 2011	Jan. 03, 2010
Periodic Financial Data [Abstract]
Total revenues	$ 376,326	$ 384,933	$ 389,186	$ 347,388	$ 362,405	$ 381,131	$ 501,748	$ 479,970	$ 1,652,193	$ 1,570,894	$ 1,404,057
Operating margin	103,359	110,694	111,606	94,153	100,336	107,994	144,857	136,106	470,516	438,589	386,976
Income before provision for income taxes	34,930	41,076	43,735	27,208	34,320	39,562	48,065	37,855	167,806	138,945	135,522
Net income	$ 22,091	$ 25,248	$ 27,111	$ 16,600	$ 22,625	$ 24,519	$ 30,911	$ 24,173	$ 105,361	$ 87,917	$ 79,744
Earnings per common share - basic	$ 0.37	$ 0.42	$ 0.46	$ 0.28	$ 0.39	$ 0.42	$ 0.54	$ 0.41	$ 1.79	$ 1.50	$ 1.39
Earnings per common share - diluted	$ 0.36	$ 0.40	$ 0.43	$ 0.27	$ 0.37	$ 0.41	$ 0.52	$ 0.39	$ 1.71	$ 1.45	$ 1.38
Common stock dividends declared per share