Discontinued Operations (Summary Of Statements Of Operations As Discontinued Operations) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Income (loss) from discontinued operations, net of income taxes	$ 14,003	$ (27,411)	$ 24,896
Less: Net income attributable to noncontrolling interests	1,244	1,377	853
Net income (loss) attributable to Tile Coatings business	42,799	6,038	80,093
Discontinued Operations [Member] | Tile Coatings [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Net sales	440,501	491,493	537,712
Cost of sales	327,505	388,959	420,168
Gross profit	112,996	102,534	117,544
Selling, general and administrative expenses	72,033	71,591	58,858
Restructuring and impairment charges	2,290	44,378	6,179
Interest expense	10,650	11,556	12,835
Interest earned	(184)	(122)	(125)
Foreign currency losses (gains), net	6,608	(2,397)	1,852
Miscellaneous expense, net	2,281	2,127	3,896
Income (loss) from discontinued operations before income taxes	19,318	(24,599)	34,049
Income tax expense	5,315	2,812	9,153
Income (loss) from discontinued operations, net of income taxes	14,003	(27,411)	24,896
Less: Net income attributable to noncontrolling interests	171	290	2
Net income (loss) attributable to Tile Coatings business	$ 13,832	$ (27,701)	$ 24,894