| Intangible Assets | 
Intangible Assets 
The following table summarizes acquired intangible assets as follows: 
 
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September 26, 2020 | 
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December 31, 2019 | 
 
| (In thousands) | 
 Weighted 
Average Life 
 | 
 | 
 Gross Carrying 
Amount 
 | 
 | 
 Accumulated 
Amortization 
 | 
 | 
 Gross Carrying 
Amount 
 | 
 | 
 Accumulated 
Amortization 
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| Patents | 
11 years | 
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$ | 
2,146  | 
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$ | 
1,869  | 
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$ | 
2,146  | 
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$ | 
1,804  | 
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| Non-compete Agreement | 
4 years | 
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11,091  | 
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9,627  | 
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11,318  | 
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7,696  | 
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| Trade Names | 
10 years | 
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11,467  | 
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7,290  | 
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11,438  | 
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6,550  | 
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| Completed and Unpatented Technology | 
9 years | 
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48,250  | 
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24,633  | 
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48,201  | 
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21,196  | 
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| Customer Relationships | 
15 years | 
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142,528  | 
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57,708  | 
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142,212  | 
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50,776  | 
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| Total Intangible Assets | 
12 years | 
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$ | 
215,482  | 
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$ | 
101,127  | 
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$ | 
215,315  | 
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$ | 
88,022  | 
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All acquired intangible assets other than goodwill and one trade name are being amortized. Amortization expense for acquired intangibles is summarized as follows: 
 
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Nine Months Ended | 
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Three Months Ended | 
 
(In thousands)  | 
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September 26, 2020 | 
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September 28, 2019 | 
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September 26, 2020 | 
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September 28, 2019 | 
 
Amortization Expense  | 
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$ | 
13,024  | 
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$ | 
12,746  | 
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$ | 
4,382  | 
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$ | 
4,394  | 
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Amortization expense for acquired intangible assets expected for 2020 and for each of the next five years is summarized as follows: 
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(In thousands)  | 
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| 2020 | 
$ | 
17,220  | 
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| 2021 | 
$ | 
15,404  | 
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| 2022 | 
$ | 
14,973  | 
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| 2023 | 
$ | 
13,939  | 
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| 2024 | 
$ | 
12,917  | 
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| 2025 | 
$ | 
10,996  | 
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