Basis of Presentation and Significant Accounting Policies (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Jan. 01, 2018	Dec. 31, 2017
Balance Sheet
Accounts receivable, net	$ 291,094		$ 291,094		$ 347,668	$ 346,687
Inventories	376,542		376,542		371,659	372,183
Deferred Income Tax Assets, Net	94,440		94,440		95,368	21,001
Other assets	94,626		94,626		58,864	59,869
Deferred revenue	30,493		30,493		24,826	25,614
Deferred income taxes	14,696		14,696		14,208	12,496
Pension and other long term liabilities	67,160		67,160		51,842	59,872
Retained earnings	2,055,139		2,055,139		1,937,681	1,856,756
Income Statement
Revenue	434,898	$ 464,712	1,327,223	$ 1,305,650
Cost of goods sold	212,824	241,821	654,684	684,706
Income tax provision	12,267	21,004	39,077	46,124
Net earnings	73,151	$ 63,529	183,909	$ 157,513
Calculated under Revenue Guidance in Effect before Topic 606
Balance Sheet
Accounts receivable, net	288,602		288,602			346,687
Inventories	376,826		376,826			372,183
Deferred Income Tax Assets, Net						21,001
Other assets						59,869
Deferred revenue	30,493		30,493			25,614
Deferred income taxes	14,148		14,148			12,496
Pension and other long term liabilities						59,872
Retained earnings	2,053,479		2,053,479			$ 1,856,756
Income Statement
Revenue	434,543		1,325,712
Cost of goods sold	212,747		654,400
Income tax provision	12,209		38,819
Net earnings	72,931		182,940
Difference between Revenue Guidance in Effect before and after Topic 606 | Accounting Standards Update 2014-09
Balance Sheet
Accounts receivable, net	2,492		2,492		981
Inventories	(284)		(284)		(524)
Deferred Income Tax Assets, Net					0
Other assets					0
Deferred revenue	0		0		(788)
Deferred income taxes	548		548		290
Pension and other long term liabilities					0
Retained earnings	1,660		1,660		955
Income Statement
Revenue	355		1,511
Cost of goods sold	77		284
Income tax provision	58		258
Net earnings	$ 220		$ 969
Restatement Adjustment | Accounting Standards Update 2016-16
Balance Sheet
Accounts receivable, net					0
Inventories					0
Deferred Income Tax Assets, Net					74,367
Other assets					(1,005)
Deferred revenue					0
Deferred income taxes					1,422
Pension and other long term liabilities					(8,030)
Retained earnings					$ 79,970