Commitments, contingencies and other (Narrative) (Details)	3 Months Ended	0 Months Ended	1 Months Ended	0 Months Ended		1 Months Ended				9 Months Ended
	Sep. 29, 2012 BELGIUM Foreign Tax Authority [Member] EUR (€)	May 20, 2014 BELGIUM Foreign Tax Authority [Member] 2008 [Member] EUR (€)	Jan. 31, 2012 BELGIUM Foreign Tax Authority [Member] 2008 [Member] EUR (€)	Dec. 28, 2012 BELGIUM Foreign Tax Authority [Member] 2005 [Member] EUR (€)	Dec. 28, 2012 BELGIUM Foreign Tax Authority [Member] 2009 [Member] EUR (€)	Dec. 31, 2013 BELGIUM Foreign Tax Authority [Member] 2006 [Member] EUR (€)	Dec. 31, 2013 BELGIUM Foreign Tax Authority [Member] 2007 [Member] EUR (€)	Dec. 31, 2013 BELGIUM Foreign Tax Authority [Member] 2010 [Member] EUR (€)	Mar. 21, 2011 Polyurethane Foam Antitrust Litigation [Member] claim	Sep. 27, 2014 Polyurethane Foam Antitrust Litigation [Member] USD ($)
Commitments And Contingencies [Line Items]
Number of class action complaints									2
Damages claimed										$ 1,200,000,000
Assessment received from Belgian tax authority (in euros)		30,132,000	23,789,000	46,135,000	35,567,000	38,817,000	39,635,000	43,117,000
Interest income earned on deposits related to tax assessment	€ 1,583,000