Income Taxes (Principal Components Of The Company's Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Accruals not yet tax deductible	$ 92,158	$ 141,961
Pension and postretirement benefit plan obligations	37,357	88,741
Stock compensation	12,669	19,051
Net operating loss carryforward	33,171	33,587
Valuation allowance	(21,561)	(30,953)
Other, net	52,422	56,903
Deferred tax assets, net	206,216	309,290
Deferred tax liabilities:
Depreciation, tax in excess of book	(88,989)	(139,268)
Other	(8,154)	(2,293)
Deferred tax liabilities, net	(97,143)	(141,561)
Total	$ 109,073	$ 167,729