Income Taxes (Deferred Tax Assets And Deferred Tax Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Accounts receivable	$ 18,481	$ 23,521
Inventories	41,169	48,673
Employee benefits	42,191	76,143
Accrued expenses and other	52,635	72,258
Deductible state tax and interest benefit	2,087	5,186
Intangibles	22,119	12,874
Federal, foreign and state net operating losses and credits	530,978	456,130
Gross deferred tax assets	709,660	694,785
Valuation allowance	(362,963)	(289,078)
Net deferred tax assets	346,697	405,707
Inventories	(14,423)	(13,099)
Plant and equipment	(397,668)	(426,087)
Intangibles	(170,817)	(243,339)
Other liabilities	(31,702)	(50,041)
Gross deferred tax liabilities	(614,610)	(732,566)
Net deferred tax liability	$ (267,913)	$ (326,859)