Impact on Earnings from Interest Rate Swaps (Details) (Interest Rate Swap [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 29, 2013	Jun. 30, 2012	Jun. 29, 2013	Jun. 30, 2012
Other Comprehensive Income
Derivative Instruments, Gain (Loss) [Line Items]
Gain/(loss) recognized in accumulated other comprehensive income	$ 1,509	$ (701)	$ 608	$ (1,152)
Interest Expense
Derivative Instruments, Gain (Loss) [Line Items]
Gain/(loss) reclassified from accumulated other comprehensive income (effective portion)	(521)	(510)	(912)	(1,017)
Other Expense
Derivative Instruments, Gain (Loss) [Line Items]
Gain/(loss) recognized in income (ineffective portion)	$ 39	$ 14	$ 34	$ 13