Segment reporting (Summary of segment information) (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 03, 2015 USD ($)	Sep. 27, 2014 USD ($)	Oct. 03, 2015 USD ($) segment	Sep. 27, 2014 USD ($)	Dec. 31, 2014 USD ($)
Segment Reporting [Abstract]
Number of reportable segments | segment			3
Segment Reporting Information [Line Items]
Net sales	$ 2,150,656	$ 1,990,658	$ 6,073,566	$ 5,852,000
Operating income (loss)	288,734	213,693	588,324	566,676
Assets	10,064,482		10,064,482		$ 8,285,544
Operating Segments [Member] | Global Ceramic Segment [Member]
Segment Reporting Information [Line Items]
Net sales	791,538	779,842	2,301,168	2,271,660
Operating income (loss)	120,055	101,254	326,571	268,320
Assets	3,938,242		3,938,242		3,542,594
Operating Segments [Member] | Flooring NA Segment [Member]
Segment Reporting Information [Line Items]
Net sales	955,099	886,317	2,722,347	2,562,560
Operating income (loss)	125,910	83,623	145,861	207,578
Assets	3,195,904		3,195,904		2,587,151
Operating Segments [Member] | Flooring ROW Segment [Member]
Segment Reporting Information [Line Items]
Net sales	404,026	326,146	1,050,390	1,021,951
Operating income (loss)	55,471	35,046	153,164	113,909
Assets	2,699,255		2,699,255		1,909,487
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Intersegment sales	(7)	(1,647)	(339)	(4,171)
Operating income (loss)	(12,702)	$ (6,230)	(37,272)	$ (23,131)
Assets	$ 231,081		$ 231,081		$ 246,312