Segment reporting (Summary of segment information) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 29, 2013	Jun. 30, 2012	Jun. 29, 2013 segment	Jun. 30, 2012	Dec. 31, 2012
Segment Reporting Information [Line Items]
Net sales	$ 1,976,299	$ 1,469,793	$ 3,463,114	$ 2,878,828
Intersegment sales	(25,717)	(23,362)	(50,592)	(44,556)
Operating income (loss)	133,198	107,718	220,040	179,694
Assets	8,508,964		8,508,964		6,303,684
Number of reporting segments			3
Carpet Segment [Member]
Segment Reporting Information [Line Items]
Net sales	770,868	734,493	1,466,202	1,434,373
Operating income (loss)	54,862	37,136	80,100	62,418
Assets	1,803,212		1,803,212		1,721,214
Ceramic Segment [Member]
Segment Reporting Information [Line Items]
Net sales	760,168	404,288	1,172,049	797,213
Operating income (loss)	46,304	36,432	76,280	62,460
Assets	3,832,888		3,832,888		1,731,258
Laminate and Wood Segment [Member]
Segment Reporting Information [Line Items]
Net sales	470,980	354,374	875,455	691,798
Operating income (loss)	41,362	40,575	80,055	67,721
Assets	2,691,553		2,691,553		2,672,389
Corporate and Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Operating income (loss)	(9,330)	(6,425)	(16,395)	(12,905)
Assets	$ 181,311		$ 181,311		$ 178,823