Earnings Per Share (Details) (USD $) In Thousands, except 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
Earnings Per Share [Line Items]
Net income available to common stockholders - basic and diluted	$ 22,091	$ 25,248	$ 27,111	$ 16,600	$ 22,625	$ 24,519	$ 30,911	$ 24,173	$ 105,361	$ 87,917	$ 79,744
Weighted average number of common shares									58,918,038	58,467,769	57,409,448
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
Diluted weighted average number of common shares									61,653,519	60,815,898	57,827,697
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
Diluted Earnings Per Share [Member]
Earnings Per Share [Line Items]
Anti-dilutive stock options to purchase common stock not included in calculating earnings per share									206,800	674,710	9,186,229