Discontinued Operations (Summary Of Assets And Liabilities As Discontinued Operations) (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash and cash equivalents	$ 8,200		$ 8,200
Current assets held-for-sale	285,229	$ 291,420
Deferred income taxes	103,380	98,714
Non-current assets held-for-sale	163,103	157,931
Current liabilities held-for-sale	89,481	133,780
Non-current liabilities held-for-sale	69,535	38,341
Tile Coatings [Member] | Discontinued Operations, Held-For-Sale [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash and cash equivalents	8,200	8,200
Accounts receivable, net	186,457	156,645
Inventories	84,422	101,127
Other receivables	3,331	22,442
Other current assets	2,819	3,006
Current assets held-for-sale	285,229	291,420
Property, plant and equipment, net	100,944	96,762
Goodwill	3	3
Amortizable intangible assets, net	40,947	39,692
Deferred income taxes	14,695	14,425
Other non-current assets	6,514	7,049
Non-current assets held-for-sale	163,103	157,931
Total assets held-for-sale	448,332	449,351
Loans payable and current portion of long-term debt	3,759	3,678
Accounts payable	66,082	96,998
Accrued payrolls	7,597	4,838
Accrued expenses and other current liabilities	12,043	28,266
Current liabilities held-for-sale	89,481	133,780
Long-term debt, less current portion	54,755	25,805
Postretirement and pension liabilities	8,378	7,473
Other non-current liabilities	6,402	5,063
Non-current liabilities held-for-sale	69,535	38,341
Total liabilities held-for-sale	$ 159,016	$ 172,121