Earnings Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Jan. 01, 2011	Jan. 02, 2010
Earnings Per Share
Net income	$ 35,472	$ 73,242	$ 73,092
Shares used in computing basic earnings per share (in shares)	43,421,000	44,845,000	45,023,000
Effect of dilutive securities:
Stock options and awards (in shares)	1,411,000	1,897,000	1,519,000
Shares used in computing diluted earnings per share (in shares)	44,832,000	46,742,000	46,542,000
Earnings per share:
Basic (in dollars per share)	$ 0.82	$ 1.63	$ 1.62
Diluted (in dollars per share)	$ 0.79	$ 1.57	$ 1.57
Weighted-average dilutive potential shares excluded from computation of diluted earning per share (in shares)	400,000	600,000	2,100,000