Operating Segments and Related Information (Details 3) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2018
Segment Reporting, Asset Reconciling Item [Line Items]
Consolidated segment operating income	$ 473,981	$ 435,129	$ 386,157
Unallocated corporate expense	(106,994)	(87,184)	(65,012)
Amortization of Intangible Assets	24,700	27,500	18,400
Purchase accounting adjustments	0	(1,992)	(3,230)
Restructuring expenses	$ (4,854)	$ (625)	$ (1,431)
Product Liability Contingency, Accrual, Assumptions	-1946	-4388	-2500
Operating Income (Loss)	$ 318,606	$ 289,961	$ 295,718
Gain (Loss) on Disposition of Business	(13,708)	(23,588)	0
Other Nonoperating Expense	(11,503)	(10,896)	(19,761)
Consolidated earnings before income taxes	307,103	279,065	275,957
Goodwill	904,571	909,811	801,406	$ 909,811
Cash and Cash Equivalents	512,144	519,090
Disposal Group, Including Discontinued Operation, Assets, Current	2,032	67,344
Prepaid expense and other current assets, excluding demo assets	67,413	44,361
Property, Plant and Equipment, Net	247,407	263,996
Deferred income taxes, net	100,620	21,001		95,368
Intangible assets, net	146,845	168,130
Other assets	89,152	59,869
Assets	2,781,242	2,810,026
Acquired Intangible Assets [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Amortization of Intangible Assets	(24,524)	(27,391)	(18,266)
Intangible assets, net	144,875	165,228
Total Segments [Member]
Segment Reporting, Asset Reconciling Item [Line Items]
Restructuring expenses	(8,203)
Operating Income (Loss)	473,981	435,129	386,157
BU assets (accounts receivable, inventories and demonstration assets, net)	711,058	756,424
Goodwill	904,571
BU assets (AR, inventories, demo assets and goodwill, net)	1,615,629	756,424
Industrial
Segment Reporting, Asset Reconciling Item [Line Items]
Operating Income (Loss)	216,880	199,903	156,749
BU assets (accounts receivable, inventories and demonstration assets, net)	266,457	287,439
Goodwill	391,603			389,575
Government and defense
Segment Reporting, Asset Reconciling Item [Line Items]
Operating Income (Loss)	199,702	179,160	176,749
BU assets (accounts receivable, inventories and demonstration assets, net)	307,041	332,044
Goodwill	284,188			291,229
Commercial
Segment Reporting, Asset Reconciling Item [Line Items]
Operating Income (Loss)	57,399	56,066	$ 52,659
BU assets (accounts receivable, inventories and demonstration assets, net)	137,560	$ 136,941
Goodwill	$ 228,780			$ 229,007