Goodwill and intangible assets (Narrative) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 29, 2014	Dec. 31, 2013
Goodwill [Line Items]
Goodwill allocation	$ 12
Goodwill	1,721,792	1,736,092
Laminate and Wood Segment [Member]
Goodwill [Line Items]
Enterprise value	303
Goodwill allocation	2,509
Goodwill	809,174	808,210
Unidentified Wood Business [Member] | Laminate and Wood Segment [Member]
Goodwill [Line Items]
Goodwill	$ 1,396