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Supplementary balance sheet detail (Schedule Of Amounts Recognized In Balance Sheet) (Details) - USD ($) $ in Thousands | Jun. 30, 2018 | Dec. 31, 2017 | Dec. 31, 2016
--- | --- | --- | ---
Balance Sheet Related Disclosures [Abstract] |  |  |
Raw materials and supplies | $ 73,349 | $ 39,434 | $ 54,469
Work in process | 109,091 | 85,852 | 52,379
Finished goods | 68,888 | 48,865 | 49,263
Total | 251,328 | 174,151 | 156,111
Prepaid expenses |  | 9,505 | 6,096
Value added tax and other indirect taxes receivable |  | 18,627 | 12,984
Spare parts inventory |  | 11,010 |
Other current assets |  | 5,730 | 2,585
Prepaid expenses and other current assets | 54,304 | 44,872 | 21,665
Land and improvements |  | 46,599 | 43,737
Buildings |  | 59,608 | 55,440
Machinery and equipment and other |  | 495,069 | 460,892
Construction in progress |  | 41,375 | 25,635
Property, Plant and Equipment, Gross, Total | 667,664 | 642,651 | 585,704
Payrolls (including incentive programs) |  | 14,196 | 4,802
Employee benefits |  | 4,684 | 11,439
Customer prepayments |  | 20,784 |
Other |  | 13,562 | 14,278
Other accrued liabilities |  | 53,226 | 30,519
Postretirement benefits |  | 20,508 | 19,002
Pension and related benefits |  | 36,116 | 45,876
Other |  | 12,283 | 17,270
Other Liabilities, Noncurrent, Total | $ 71,006 | $ 68,907 | $ 82,148

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