Impact on Earnings from Interest Rate Swaps (Details) (Interest Rate Swap, USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jul. 02, 2011	Jun. 30, 2012	Jul. 02, 2011
Other Comprehensive Income
Derivative Instruments, Gain (Loss) [Line Items]
Gain/(loss) recognized in accumulated other comprehensive income	$ (701)	$ (1,286)	$ (1,152)	$ (1,920)
Interest Expense
Derivative Instruments, Gain (Loss) [Line Items]
Gain/(loss) reclassified from accumulated other comprehensive income (effective portion)	(510)	(787)	(1,017)	(1,577)
Other Expense
Derivative Instruments, Gain (Loss) [Line Items]
Gain/(loss) recognized in income (ineffective portion)	$ 14	$ (37)	$ 13	$ 3