Significant Accounting Policies Revenue From Contracts with Customers ASU 2014-09 (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017
Summary Of Significant Accounting Policies [Line Items]
Trade accounts receivable, net	$ 783,306	$ 454,637	$ 702,307
Inventories	690,378	721,290	704,384
Accrued liabilities	101,895	123,602	122,129
Deferred income taxes	279,449	262,394	395,181
Retained earnings	1,970,875	$ 1,809,845	$ 1,651,760
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] \| Accounting Standards Update 2014-09 [Member]
Summary Of Significant Accounting Policies [Line Items]
Trade accounts receivable, net	69,400
Inventories	(56,600)
Accrued liabilities	900
Deferred income taxes	2,800
Retained earnings	$ 9,100

Summary Of Significant Accounting Policies [Line Items]

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Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.

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Carrying value as of the balance sheet date of obligations incurred and payable, pertaining to costs that are statutory in nature, are incurred on contractual obligations, or accumulate over time and for which invoices have not yet been received or will not be rendered. Examples include taxes, interest, rent and utilities. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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