Income Taxes Reconciliation of unrecognized tax benefits (Details) (USD $)	3 Months Ended	12 Months Ended
	Sep. 26, 2014	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 30, 2011
Reconciliation of Unrecognized Tax Benefits [Roll Forward]
Balance, beginning of year		$ (2,192,000)	$ (11,209,000)	$ (11,395,000)
Reductions for expiration of the applicable statute of limitations	9,000,000	0	8,954,000	0
Reductions for tax positions of prior years		0	145,000	466,000
Additions for tax positions of current year		(336,000)	0	(243,000)
Additions for tax positions of prior years		(252,000)	0	0
Foreign currency translation		(312,000)	(82,000)	(37,000)
Balance, end of year		(2,468,000)	(2,192,000)	(11,209,000)
Unrecognized tax benefits that would impact effective tax rate if we prevail		2,500,000	2,200,000
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense [Abstract]
Unrecognized tax benefits, income tax penalties and interest accrued		200,000	200,000	3,300,000
Unrecognized tax benefits, income tax penalties and interest expense		100,000	3,200,000	400,000
Unrecognized tax benefits reductions in interest and penalties accrued resulting from lapse of applicable statute of limitations	3,200,000
Time period that uncertain tax positions not expected to materially change		12 months
Tax Year 2011 | Tax and Customs Administration, Netherlands
Unrecognized Tax Benefits, Tax Examination [Abstract]
Income tax examination, likelihood of favorable settlement					3,300,000
Tax Year 2012 | Tax and Customs Administration, Netherlands
Unrecognized Tax Benefits, Tax Examination [Abstract]
Income tax examination, likelihood of favorable settlement				$ 3,500,000