Segment reporting (Summary of segment information) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 28, 2014	Jun. 29, 2013	Jun. 28, 2014 segment	Jun. 29, 2013	Dec. 31, 2013
Segment Reporting [Abstract]
Number of reporting segments			3
Segment Reporting Information [Line Items]
Net sales	$ 2,048,247	$ 1,976,299	$ 3,861,342	$ 3,463,114
Intersegment sales	(30,042)	(25,717)	(54,975)	(50,592)
Operating income (loss)	222,248	133,198	352,983	220,040
Assets	8,881,681		8,881,681		8,494,177
Carpet Segment [Member]
Segment Reporting Information [Line Items]
Net sales	780,308	770,868	1,455,234	1,466,202
Operating income (loss)	62,826	54,862	97,097	80,100
Assets	1,960,106		1,960,106		1,786,085
Ceramic Segment [Member]
Segment Reporting Information [Line Items]
Net sales	796,724	760,168	1,491,818	1,172,049
Operating income (loss)	106,407	46,304	167,066	76,280
Assets	3,900,387		3,900,387		3,787,785
Laminate and Wood Segment [Member]
Segment Reporting Information [Line Items]
Net sales	501,257	470,980	969,265	875,455
Operating income (loss)	60,843	41,362	104,962	80,055
Assets	2,818,129		2,818,129		2,716,759
Corporate and Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Operating income (loss)	(7,828)	(9,330)	(16,142)	(16,395)
Assets	$ 203,059		$ 203,059		$ 203,548