Property and Equipment (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 27, 2013	Sep. 28, 2012	Sep. 27, 2013	Sep. 28, 2012	Dec. 31, 2012
Property, Plant and Equipment [Line Items]
Property and equipmpent, gross	$ 491,539,000		$ 491,539,000		$ 477,280,000
Accumulated depreciation	(292,897,000)		(292,897,000)		(271,132,000)
Property and equipment, net	198,642,000		198,642,000		206,148,000
Depreciation and Amortization	10,800,000	8,700,000	31,200,000	23,700,000
Land and land rights [Member]
Property, Plant and Equipment [Line Items]
Property and equipmpent, gross	23,157,000		23,157,000		23,157,000
Building [Member]
Property, Plant and Equipment [Line Items]
Property and equipmpent, gross	158,566,000		158,566,000		159,247,000
Equipment and software [Member]
Property, Plant and Equipment [Line Items]
Property and equipmpent, gross	269,758,000		269,758,000		256,725,000
Office furniture and fixtures [Member]
Property, Plant and Equipment [Line Items]
Property and equipmpent, gross	24,338,000		24,338,000		24,531,000
Leasehold improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipmpent, gross	12,303,000		12,303,000		11,915,000
Construction in progress [Member]
Property, Plant and Equipment [Line Items]
Property and equipmpent, gross	$ 3,417,000		$ 3,417,000		$ 1,705,000