Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

Name:	us-gaap_AccountsPayableCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

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.

New Accounting Pronouncements (Condensed Consolidated Balance Sheet) (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Mar. 31, 2017	Dec. 31, 2016
Condensed Consolidated Balance Sheets [Abstract]
Cash and cash equivalents	$ 676,327	$ 742,546	$ 752,477	$ 681,433
Accounts receivable, net	403,767	436,560
Contract assets	147,623	146,496
Inventories, net	305,980	268,917
Prepaid expenses and other assets	31,729	36,018
Income taxes receivable	66	120
Property, plant and equipment, net	200,422	186,473
Goodwill	191,616	191,616
Deferred income taxes	4,034	4,034
Other, net	96,442	96,524
Assets	2,058,006	2,109,304
Current installments of long-term debt and capital lease obligations	19,746	18,274
Accounts payable	368,625	362,701
Income taxes payable	12,808	11,663
Accrued liabilities	83,652	85,679
Long-term debt and capital lease obligations, less current installments	187,601	193,406
Other long-term liabilities	90,270	89,749
Deferred income taxes	47,973	8,694
Total liabilities		770,166
Common stock	4,757	4,914
Additional paid-in capital	608,092	634,192
Retained earnings	640,466	708,181
Total shareholders' equity	1,247,331	1,339,138
Accumulated other comprehensive loss	(5,984)	(8,149)
Total liabilities and shareholders' equity	$ 2,058,006	2,109,304
Accounting Standards Update 2014-09 [Member] \| As Previously Reported [Member] \| Calculated Under Revenue Guidance In Effect Before Topic 606 [Member]
Condensed Consolidated Balance Sheets [Abstract]
Cash and cash equivalents		742,546	752,477	681,433
Accounts receivable, net		436,560
Contract assets		0
Inventories, net		397,181
Prepaid expenses and other assets		42,263
Income taxes receivable		120
Property, plant and equipment, net		186,473
Goodwill		191,616
Deferred income taxes		4,034
Other, net		96,524
Assets		2,097,317
Current installments of long-term debt and capital lease obligations		18,274
Accounts payable		362,701
Income taxes payable		11,662
Accrued liabilities		85,679
Long-term debt and capital lease obligations, less current installments		193,406
Other long-term liabilities		89,749
Deferred income taxes		7,027
Total liabilities		768,498
Common stock		4,914
Additional paid-in capital		634,192
Retained earnings		697,862
Total shareholders' equity		1,328,819
Accumulated other comprehensive loss		(8,149)
Total liabilities and shareholders' equity		2,097,317
Accounting Standards Update 2014-09 [Member] \| Restatement Adjustment [Member] \| Adjustments [Member]
Condensed Consolidated Balance Sheets [Abstract]
Cash and cash equivalents		0	$ 0	$ 0
Accounts receivable, net		0
Contract assets		146,496
Inventories, net		(128,264)
Prepaid expenses and other assets		(6,245)
Income taxes receivable		0
Property, plant and equipment, net		0
Goodwill		0
Deferred income taxes		0
Other, net		0
Assets		11,987
Current installments of long-term debt and capital lease obligations		0
Accounts payable		0
Income taxes payable		1
Accrued liabilities		0
Long-term debt and capital lease obligations, less current installments		0
Other long-term liabilities		0
Deferred income taxes		1,667
Total liabilities		1,668
Common stock		0
Additional paid-in capital		0
Retained earnings		10,319
Total shareholders' equity		10,319
Accumulated other comprehensive loss		0
Total liabilities and shareholders' equity		$ 11,987