Derivative Financial Instruments (Effect of Derivatives on Income Statement) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Jan. 01, 2011	Jan. 02, 2010
Derivative Instruments, Gain (Loss) [Line Items]
Before-tax Gain (Loss) Recognized in OCI on Derivative (Effective Portion)	$ (937)	$ (698)
Before-Tax Gain (Loss) Reclassified from AOCI Into Income (Effective Portion)	214	(2,483)
Gain (Loss) Recognized in Income on Derivative (Ineffective Portion)	0	2
Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Before-tax Gain (Loss) Recognized in OCI on Derivative (Effective Portion)	(10)	(1,367)	(1,100)
Gain (Loss) Recognized in Income on Derivative (Ineffective Portion)	0	0	0
Interest Rate Contract [Member] | Interest Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Before-Tax Gain (Loss) Reclassified from AOCI Into Income (Effective Portion)	(898)	(2,088)	(1,658)
Diesel Fuel Swap [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Before-tax Gain (Loss) Recognized in OCI on Derivative (Effective Portion)	(927)	669
Diesel Fuel Swap [Member] | Selling and Administrative Expense [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Before-Tax Gain (Loss) Reclassified from AOCI Into Income (Effective Portion)	1,112	(395)
Gain (Loss) Recognized in Income on Derivative (Ineffective Portion)	$ 0	$ 2