Segment Reporting (Summary of segment information) (Details) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jul. 01, 2017 USD ($)	Apr. 01, 2017 USD ($)	Dec. 31, 2016 USD ($)	Oct. 01, 2016 USD ($)	Jul. 02, 2016 USD ($)	Apr. 02, 2016 USD ($)	Dec. 31, 2017 USD ($) segment	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Segment Reporting Information [Line Items]
Number of reporting segments | segment									3
Net sales	$ 2,369,097	$ 2,448,510	$ 2,453,038	$ 2,220,645	$ 2,182,566	$ 2,294,139	$ 2,310,336	$ 2,172,046	$ 9,491,290	$ 8,959,087	$ 8,071,563
Operating income (loss)									1,354,173	1,279,943	837,566
Depreciation and amortization									446,672	409,467	362,647
Capital expenditures (excluding acquisitions)									905,998	672,125	503,657
Assets	12,094,853				10,230,596				12,094,853	10,230,596	9,934,400
Long-lived assets	6,742,249				5,644,774				6,742,249	5,644,774	5,440,483
Soft surface
Segment Reporting Information [Line Items]
Net sales									3,655,525	3,414,956	3,056,946
Tile
Segment Reporting Information [Line Items]
Net sales									3,485,245	3,258,136	3,094,389
Laminate and wood
Segment Reporting Information [Line Items]
Net sales									2,350,520	2,285,995	1,920,228
United States
Segment Reporting Information [Line Items]
Net sales									6,009,165	5,842,683	5,399,561
Long-lived assets	3,339,363				3,092,902				3,339,363	3,092,902	2,945,783
Belgium
Segment Reporting Information [Line Items]
Long-lived assets	1,705,947				1,371,397				1,705,947	1,371,397	1,377,533
All other countries
Segment Reporting Information [Line Items]
Net sales									3,482,125	3,116,404	2,672,002
Long-lived assets	1,696,939				1,180,475				1,696,939	1,180,475	1,117,167
Operating segments | Global Ceramic
Segment Reporting Information [Line Items]
Net sales									3,405,100	3,174,706	3,012,859
Operating income (loss)									525,401	478,448	414,154
Depreciation and amortization									161,913	135,370	118,801
Capital expenditures (excluding acquisitions)									310,650	263,401	247,829
Assets	4,838,310				4,024,859				4,838,310	4,024,859	3,846,133
Operating segments | Flooring NA
Segment Reporting Information [Line Items]
Net sales									4,010,858	3,865,746	3,602,112
Operating income (loss)									540,337	505,115	264,271
Depreciation and amortization									159,980	148,067	137,064
Capital expenditures (excluding acquisitions)									355,941	248,843	148,598
Assets	3,702,137				3,410,856				3,702,137	3,410,856	3,164,525
Operating segments | Flooring ROW
Segment Reporting Information [Line Items]
Net sales									2,075,452	1,918,635	1,456,898
Operating income (loss)									329,054	333,091	203,370
Depreciation and amortization									114,794	116,048	97,239
Capital expenditures (excluding acquisitions)									221,763	144,207	95,447
Assets	3,245,424				2,689,592				3,245,424	2,689,592	2,805,246
Corporate and intersegment eliminations
Segment Reporting Information [Line Items]
Operating income (loss)									(40,619)	(36,711)	(44,229)
Assets	$ 308,982				$ 105,289				308,982	105,289	118,496
Intersegment sales
Segment Reporting Information [Line Items]
Net sales									(120)	0	(306)
Corporate
Segment Reporting Information [Line Items]
Depreciation and amortization									9,985	9,982	9,543
Capital expenditures (excluding acquisitions)									$ 17,644	$ 15,674	$ 11,783