CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands		3 Months Ended
		Mar. 29, 2020	Mar. 31, 2019
Revenues:
Total revenues	[1]	$ 704,355	$ 494,099
Cost of revenues:
Total cost of revenues (exclusive of acquired intangible assets amortization shown separately below)		298,805	206,464
Gross profit		405,550	287,635
Operating expenses:
Selling and administrative		111,388	102,013
Engineering and development		85,159	76,791
Acquired intangible assets amortization		9,891	10,634
Restructuring and other		(7,606)	5,112
Total operating expenses		198,832	194,550
Income from operations		206,718	93,085
Non-operating (income) expense:
Interest income		(2,751)	(4,989)
Interest expense		5,551	5,520
Other (income) expense, net		6,849	(1,425)
Income before income taxes		197,069	93,979
Income tax provision (benefit)		20,878	(15,159)
Net income		$ 176,191	$ 109,138
Net income per common share:
Basic		$ 1.06	$ 0.63
Diluted		$ 0.97	$ 0.62
Weighted average common shares—basic		166,589	173,532
Weighted average common shares—diluted		180,736	176,972
Cash dividend declared per common share		$ 0.10	$ 0.09
Product [Member]
Revenues:
Total revenues		$ 610,906	$ 393,442
Cost of revenues:
Total cost of revenues (exclusive of acquired intangible assets amortization shown separately below)		259,996	165,368
Service [Member]
Revenues:
Total revenues		93,449	100,657
Cost of revenues:
Total cost of revenues (exclusive of acquired intangible assets amortization shown separately below)		$ 38,809	$ 41,096

[1] Includes $1.8 million and $1.7 million in 2020 and 2019, for leases of Teradyne’s systems recognized outside ASC 606 “Revenue from Contracts with Customers.