Discontinued Operations (Summary Of Statements Of Operations As Discontinued Operations) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Income (loss) from discontinued operations, net of income taxes	$ 5,367	$ (3,520)	$ 2,350	$ 1,305
Less: Net income (loss) attributable to non-controlling interests	440	390	826	902
Net income (loss) attributable to Tile Coatings business	14,474	12,820	25,057	37,295
Discontinued Operations [Member] | Tile Coatings [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]
Net sales	120,163	120,389	310,167	377,499
Cost of sales	89,120	96,160	235,095	300,145
Gross profit	31,043	24,229	75,072	77,354
Selling, general and administrative expenses	18,549	20,180	52,899	53,725
Restructuring and impairment charges	269	4,161	2,306	10,751
Interest expense	2,950	2,880	7,698	8,838
Interest earned	(21)	(24)	(174)	(91)
Foreign currency losses (gains), net	113	(158)	5,074	(2,047)
Miscellaneous expense, net	173	328	1,420	598
Income (loss) from discontinued operations before income taxes	9,010	(3,138)	5,849	5,580
Income tax expense	3,643	382	3,499	4,275
Income (loss) from discontinued operations, net of income taxes	5,367	(3,520)	2,350	1,305
Less: Net income (loss) attributable to non-controlling interests	(11)	92	33	242
Net income (loss) attributable to Tile Coatings business	$ 5,378	$ (3,612)	$ 2,317	$ 1,063