Operating Segments and Related Information (Details 4) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020	Mar. 31, 2020	Dec. 31, 2019
Segment Reporting, Asset Reconciling Item [Line Items]
BU assets (accounts receivable, inventory and demo assets, Net)	$ 879,297	$ 855,918
BU assets (accounts receivable, inventory, demo assets and goodwill, Net)	2,266,144	2,250,282
Cash and cash equivalents	277,303	297,795	$ 308,615	$ 284,592
Prepaid expenses and other current assets	66,609	74,526
Property and equipment, net	269,269	267,682
Deferred Income Tax Assets, Net	35,610	36,210
Goodwill	1,386,847	1,394,364
Intangible assets, net	197,632	209,636
Other assets	116,235	116,217
Assets	3,228,802	3,252,348
Defense Technologies
Segment Reporting, Asset Reconciling Item [Line Items]
BU assets (accounts receivable, inventory and demo assets, Net)	454,023	436,595
Goodwill	742,181	742,925
Industrial Technologies
Segment Reporting, Asset Reconciling Item [Line Items]
BU assets (accounts receivable, inventory and demo assets, Net)	425,274	419,323
Goodwill	$ 644,666	$ 651,439