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Stock-Based Compensation (Tables) | 9 Months Ended
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Oct. 02, 2016
Schedule of Estimated Fair Value of TSR Performance-Based Restricted Stock Unit Awards Assumptions | The fair value was estimated using the Monte Carlo simulation model with the following assumptions:
|  | For the Nine Months Ended |
|  | October 2, 2016 |  |  | October 4, 2015 |
Risk-free interest rate |  |  | 0.97 | % |  |  | 0.77 | %
Teradyne volatility-historical |  |  | 27.0 | % |  |  | 28.2 | %
NYSE Composite Index volatility-historical |  |  | 13.1 | % |  |  | — |
Philadelphia Semiconductor Index volatility-historical |  |  | — |  |  |  | 19.7 | %
Dividend yield |  |  | 1.24 | % |  |  | 1.33 | %
Stock Options |
Fair Value of Stock Options Using Assumptions | The fair value of stock options was estimated using the Black-Scholes option-pricing model with the following assumptions:
|  | For the Nine Months Ended |
|  | October 2, 2016 |  |  | October 4, 2015 |
Expected life (years) |  |  | 5.0 |  |  |  | 4.0 |
Risk-free interest rate |  |  | 1.4 | % |  |  | 1.1 | %
Volatility-historical |  |  | 32.9 | % |  |  | 33.4 | %
Dividend yield |  |  | 1.24 | % |  |  | 1.33 | %

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- Definition Schedule Of Share Based Payment Award Total Shareholder Return Plan Valuation Assumptions [Table Text Block] + References No definition available. + Details
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- Definition Tabular disclosure of the significant assumptions used during the year to estimate the fair value of stock options, including, but not limited to: (a) expected term of share options and similar instruments, (b) expected volatility of the entity's shares, (c) expected dividends, (d) risk-free rate(s), and (e) discount for post-vesting restrictions. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (f)(2) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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