Shareholders' Equity (Narrative) (Details) (USD $)	0 Months Ended	12 Months Ended
	May 22, 2009	Dec. 31, 2011 years	Jan. 01, 2011	Jan. 02, 2010	Dec. 27, 2008
Shareholders' Equity [Abstract]
Recognized share-based compensation expense		$ 14,284,000	$ 6,747,000	$ 4,752,000
Unrecognized compensation cost related to share-based compensation		19,500,000
Share-based compensation expected to recognize over a weighted average period, years		3.1
Total income tax benefit recognized relating to share-based compensation		1,400,000
Authorized shares of common stock		2,834,026	5,000,000
Share available for future grant or payment under the various plans		1,300,000
Sale of common stock to the public	4,312,500	41,579,895	38,615,547
Sale of stock, price per share	$ 36.25
Net proceeds received by the company	$ 150,400,000			$ 150,370,000
Per share weighted average fair value of share-based incentive awards granted		$ 25.80	$ 22.62	$ 15.28
Share-based incentive awards, estimated life, years		7
Share-based incentive awards, risk-free interest rate		2.30%	2.80%	2.60%
Share-based incentive awards, expected dividend yield		1.00%	1.10%	1.50%
Share-based incentive awards, expected volatility		35.60%	34.80%	36.80%
Share-based incentive awards expiration, in years		10
Vesting period, minimum		two
Vesting period, maximum		three
Number of shares approved to be repurchased		3,000,000
Treasury stock repurchased					884,100
Average purchase price					$ 21.96
Shares issued in settlement of the conversion premium for certain convertible notes			900,000	1,400,000
Number of treasury stock shares included in issuance shares				884,100