Schedule of Segment Information (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Segment Reporting Information [Line Items]
Revenues	[1],[2]	$ 3,702,881	$ 3,121,469	$ 2,294,965
Income (loss) before taxes	[3],[4]	1,160,955	901,015	525,772
Total assets	[5]	3,809,425	3,652,346	2,787,014
Property additions		132,472	184,977	134,642
Depreciation and amortization expense		125,485	126,743	120,655
Semiconductor Test
Segment Reporting Information [Line Items]
Revenues		2,642,342	2,259,597	1,552,571
Income (loss) before taxes	[3],[4]	976,988	739,695	416,973
Total assets	[5]	1,245,596	1,070,378	784,808
Property additions		115,618	168,055	112,145
Depreciation and amortization expense		75,982	64,998	59,197
System Test
Segment Reporting Information [Line Items]
Revenues	[1]	467,739	409,729	287,455
Income (loss) before taxes	[3],[4]	163,064	152,092	93,543
Total assets	[5]	170,954	138,295	131,428
Property additions		3,905	3,092	3,059
Depreciation and amortization expense		3,156	3,426	5,518
Industrial Automation
Segment Reporting Information [Line Items]
Revenues		375,905	279,731	298,139
Income (loss) before taxes	[3],[4]	(8,167)	(24,019)	(5,916)
Total assets	[5]	701,196	712,936	671,559
Property additions		9,821	8,899	9,076
Depreciation and amortization expense		27,336	36,242	40,904
Wireless Test
Segment Reporting Information [Line Items]
Revenues	[1]	216,895	173,016	157,315
Income (loss) before taxes	[3],[4]	83,543	41,950	35,585
Total assets	[5]	107,513	106,273	97,299
Property additions		3,128	4,931	10,362
Depreciation and amortization expense		6,055	6,258	5,365
Corporate And Others [Member]
Segment Reporting Information [Line Items]
Revenues			(604)	(515)
Income (loss) before taxes	[3],[4]	(54,473)	(8,703)	(14,413)
Total assets	[5]	1,584,166	1,624,464	1,101,920
Depreciation and amortization expense		$ 12,956	$ 15,819	$ 9,671

[1] Includes $13.2 million, $10.0 million and $8.4 million in 2021, 2020 and 2019, respectively, for leases of Teradyne’s systems recognized outside of ASC 606: “Revenue from Contracts with Customers.”

[2] Revenues attributable to a country are based on location of customer site.

[3] Included in Corporate and Other are: loss on convertible debt conversions, contingent consideration adjustments, investment impairment, interest income, interest expense, pension and postretirement plan actuarial gains (losses), severance charges, net foreign exchange gains (losses), intercompany eliminations and acquisition related: (a) charges; (b) legal fees; (c) compensation.

[4] Included in income (loss) before taxes are charges and credits related to restructuring and other, loss on convertible debt conversions and inventory charges.

[5] Total assets are attributable to each segment. Corporate assets consist of cash and cash equivalents, marketable securities and certain other assets.