Valuation and Qualifying Accounts (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012	Dec. 31, 2011
Allowance for Doubtful Accounts
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	$ 4,118		$ 4,102	$ 3,752
Additions Charged to Cost and Expenses	69		78
Other				429
Deductions	1,275	[1]	62	79
Balance at End of Period	2,912		4,118	4,102
Inventory Reserve
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Period	141,838		123,512	122,434
Additions Charged to Cost and Expenses	16,592		26,849	11,601
Other	2,568		5,353	6,815
Deductions	45,141		13,876	17,338
Balance at End of Period	$ 115,857		$ 141,838	$ 123,512

[1] Based upon an improvement in the aging of accounts receivables in 2013, Teradyne reduced its allowance for doubtful accounts by approximately $1 million.