Segment reporting (Summary of segment information) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 27, 2014	Sep. 28, 2013	Sep. 27, 2014 segment	Sep. 28, 2013	Dec. 31, 2013
Segment Reporting [Abstract]
Number of reporting segments			3
Segment Reporting Information [Line Items]
Net sales	$ 1,990,658	$ 1,961,536	$ 5,852,000	$ 5,424,650
Intersegment sales	(30,607)	(28,943)	(85,582)	(79,535)
Operating income (loss)	213,693	175,903	566,676	395,943
Assets	8,701,460		8,701,460		8,494,177
Carpet Segment [Member]
Segment Reporting Information [Line Items]
Net sales	778,849	772,751	2,234,083	2,238,953
Operating income (loss)	74,082	68,836	171,179	148,936
Assets	2,016,109		2,016,109		1,786,085
Ceramic Segment [Member]
Segment Reporting Information [Line Items]
Net sales	779,842	767,005	2,271,660	1,939,054
Operating income (loss)	101,254	75,908	268,320	152,188
Assets	3,788,164		3,788,164		3,787,785
Laminate and Wood Segment [Member]
Segment Reporting Information [Line Items]
Net sales	462,574	450,723	1,431,839	1,326,178
Operating income (loss)	44,768	39,020	149,730	119,075
Assets	2,672,599		2,672,599		2,716,759
Corporate and Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Operating income (loss)	(6,411)	(7,861)	(22,553)	(24,256)
Assets	$ 224,588		$ 224,588		$ 203,548