Shareholders' Equity (Narrative) (Details)		3 Months Ended	12 Months Ended
	Jun. 30, 2002 hour	Jan. 02, 2016 USD ($) $ / shares	Dec. 31, 2016 USD ($) $ / shares shares	Jan. 02, 2016 USD ($) $ / shares shares	Jan. 03, 2015 USD ($) $ / shares shares	Jun. 12, 2009 shares	May 31, 2007 shares	Jan. 01, 2007 shares
Equity [Abstract]
Treasury stock acquired (shares)			1,082,938	550,000	1,665,850
Schedule of Shareholders' Equity [Line Items]
Amounts reclassified from accumulated other comprehensive income, net of tax | $			$ (85,638,000)	$ (105,406,000)	$ (61,155,000)
Certain officers
Schedule of Shareholders' Equity [Line Items]
Change in control percentage			20.00%
Percent of board members			0.3333
Term of employment agreement			2 years
Number of times annual salary			200.00%
Corporation's Chairman, President and CEO
Schedule of Shareholders' Equity [Line Items]
Number of times annual salary			300.00%
Director plan
Schedule of Shareholders' Equity [Line Items]
Available for future issuance (shares)							300,000
Corporation common stock issued (shares)			24,352	20,146	27,272
Purchase Plan
Schedule of Shareholders' Equity [Line Items]
Available for future issuance (shares)						1,000,000		800,000
Rights to purchase stock, minimum working hours per week | hour	20
Rights to purchase stock, minimum working months per year	5 months
Price of repurchased stock as percent of closing price on the exercise date			85.00%
Maximum amount fair value for purchase of common stock | $			$ 25,000
Common stock issued (shares)			75,098	73,874	84,065
Common stock issued at average price (in dollars per share) | $ / shares		$ 32.18	$ 31.11	$ 32.18	$ 27.92
Shares available for future issuance (shares)			298,170
Diesel hedge | Derivative financial instruments | Reclassifications from accumulated other comprehensive income (loss)
Schedule of Shareholders' Equity [Line Items]
Amounts reclassified from accumulated other comprehensive income, net of tax | $		$ 1,300,000	$ 0	$ 1,627,000