Segment reporting (Summary of segment information) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 28, 2013	Sep. 29, 2012	Sep. 28, 2013 segment	Sep. 29, 2012	Dec. 31, 2012
Segment Reporting Information [Line Items]
Net sales	$ 1,961,536	$ 1,473,493	$ 5,424,650	$ 4,352,321
Intersegment sales	(28,943)	(24,409)	(79,535)	(68,965)
Operating income (loss)	175,903	103,954	395,943	283,648
Assets	8,564,157		8,564,157		6,303,684
Number of reporting segments			3
Carpet Segment [Member]
Segment Reporting Information [Line Items]
Net sales	772,751	751,787	2,238,953	2,186,160
Operating income (loss)	68,836	43,810	148,936	106,228
Assets	1,830,869		1,830,869		1,721,214
Ceramic Segment [Member]
Segment Reporting Information [Line Items]
Net sales	767,005	417,533	1,939,054	1,214,746
Operating income (loss)	75,908	37,452	152,188	99,912
Assets	3,820,002		3,820,002		1,731,258
Laminate and Wood Segment [Member]
Segment Reporting Information [Line Items]
Net sales	450,723	328,582	1,326,178	1,020,380
Operating income (loss)	39,020	28,892	119,075	96,613
Assets	2,721,707		2,721,707		2,672,389
Corporate and Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Operating income (loss)	(7,861)	(6,200)	(24,256)	(19,105)
Assets	$ 191,579		$ 191,579		$ 178,823