| Summary of changes in goodwill | 
A summary of changes in goodwill at June 30, 2018, is as follows: 
  
| 
   
 | 
   
 | 
 Hydraulics 
 | 
   
 | 
   
 | 
 Electronics 
 | 
   
 | 
   
 | 
 Total 
 | 
   
 | 
 
| 
 Balance at December 30, 2017 
 | 
   
 | 
 $ 
 | 
 2,496 
 | 
   
 | 
   
 | 
 $ 
 | 
 106,373 
 | 
   
 | 
   
 | 
 $ 
 | 
 108,869 
 | 
   
 | 
 
| 
 Acquisition 
 | 
   
 | 
   
 | 
 248,913 
 | 
   
 | 
   
 | 
   
 | 
 — 
 | 
   
 | 
   
 | 
   
 | 
 248,913 
 | 
   
 | 
 
| 
 Currency translation 
 | 
   
 | 
   
 | 
 (11,785 
 | 
 ) 
 | 
   
 | 
   
 | 
 — 
 | 
   
 | 
   
 | 
   
 | 
 (11,785 
 | 
 ) 
 | 
 
| 
 Balance at June 30, 2018 
 | 
   
 | 
 $ 
 | 
 239,624 
 | 
   
 | 
   
 | 
 $ 
 | 
 106,373 
 | 
   
 | 
   
 | 
 $ 
 | 
 345,997 
 | 
   
 | 
 
 
 
  
 
 | 
| Schedule of intangible assets | 
At June 30, 2018, and December 30, 2017, intangible assets consisted of the following: 
  
| 
   
 | 
   
 | 
 June 30, 2018 
 | 
   
 | 
   
 | 
 December 30, 2017 
 | 
   
 | 
 
| 
   
 | 
   
 | 
 Gross carrying 
amount 
 | 
   
 | 
   
 | 
 Accumulated 
amortization 
 | 
   
 | 
   
 | 
 Net carrying 
amount 
 | 
   
 | 
   
 | 
 Gross carrying 
amount 
 | 
   
 | 
   
 | 
 Accumulated 
amortization 
 | 
   
 | 
   
 | 
 Net carrying 
amount 
 | 
   
 | 
 
| 
 Definite-lived intangibles: 
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
   
 | 
 
| 
 Trade name and brands 
 | 
   
 | 
 $ 
 | 
 55,285 
 | 
   
 | 
   
 | 
 $ 
 | 
 (3,213 
 | 
 ) 
 | 
   
 | 
 $ 
 | 
 52,072 
 | 
   
 | 
   
 | 
 $ 
 | 
 30,774 
 | 
   
 | 
   
 | 
 $ 
 | 
 (2,115 
 | 
 ) 
 | 
   
 | 
 $ 
 | 
 28,659 
 | 
   
 | 
 
| 
 Non-compete agreements 
 | 
   
 | 
   
 | 
 950 
 | 
   
 | 
   
 | 
   
 | 
 (301 
 | 
 ) 
 | 
   
 | 
   
 | 
 649 
 | 
   
 | 
   
 | 
   
 | 
 950 
 | 
   
 | 
   
 | 
   
 | 
 (206 
 | 
 ) 
 | 
   
 | 
   
 | 
 744 
 | 
   
 | 
 
| 
 Technology 
 | 
   
 | 
   
 | 
 31,217 
 | 
   
 | 
   
 | 
   
 | 
 (3,890 
 | 
 ) 
 | 
   
 | 
   
 | 
 27,327 
 | 
   
 | 
   
 | 
   
 | 
 18,435 
 | 
   
 | 
   
 | 
   
 | 
 (2,671 
 | 
 ) 
 | 
   
 | 
   
 | 
 15,764 
 | 
   
 | 
 
| 
 Supply agreement 
 | 
   
 | 
   
 | 
 21,000 
 | 
   
 | 
   
 | 
   
 | 
 (3,325 
 | 
 ) 
 | 
   
 | 
   
 | 
 17,675 
 | 
   
 | 
   
 | 
   
 | 
 21,000 
 | 
   
 | 
   
 | 
   
 | 
 (2,275 
 | 
 ) 
 | 
   
 | 
   
 | 
 18,725 
 | 
   
 | 
 
| 
 Sales order backlog 
 | 
   
 | 
   
 | 
 5,840 
 | 
   
 | 
   
 | 
   
 | 
 (3,553 
 | 
 ) 
 | 
   
 | 
   
 | 
 2,287 
 | 
   
 | 
   
 | 
   
 | 
 — 
 | 
   
 | 
   
 | 
   
 | 
 — 
 | 
   
 | 
   
 | 
   
 | 
 — 
 | 
   
 | 
 
| 
 Customer relationships 
 | 
   
 | 
   
 | 
 231,313 
 | 
   
 | 
   
 | 
   
 | 
 (5,377 
 | 
 ) 
 | 
   
 | 
   
 | 
 225,936 
 | 
   
 | 
   
 | 
   
 | 
 39,751 
 | 
   
 | 
   
 | 
   
 | 
 (2,607 
 | 
 ) 
 | 
   
 | 
   
 | 
 37,144 
 | 
   
 | 
 
| 
 Licensing agreement 
 | 
   
 | 
   
 | 
 3,716 
 | 
   
 | 
   
 | 
   
 | 
 (741 
 | 
 ) 
 | 
   
 | 
   
 | 
 2,975 
 | 
   
 | 
   
 | 
   
 | 
 3,716 
 | 
   
 | 
   
 | 
   
 | 
 (621 
 | 
 ) 
 | 
   
 | 
   
 | 
 3,095 
 | 
   
 | 
 
| 
   
 | 
   
 | 
 $ 
 | 
 349,321 
 | 
   
 | 
   
 | 
 $ 
 | 
 (20,400 
 | 
 ) 
 | 
   
 | 
 $ 
 | 
 328,921 
 | 
   
 | 
   
 | 
 $ 
 | 
 114,626 
 | 
   
 | 
   
 | 
 $ 
 | 
 (10,495 
 | 
 ) 
 | 
   
 | 
 $ 
 | 
 104,131 
 | 
   
 | 
 
 
 
  
 
 | 
| Schedule of estimated amortization expense of intangible assets | 
Amortization expense of intangible assets for the six months ended June 30, 2018, and July 1, 2017, was $10,124 and $4,348, respectively. The remaining amortization for 2018 is approximately $11,334. Total estimated amortization expense of intangible assets for the years 2019 through 2023 is presented below.   
  
| 
 Year: 
 | 
   
 | 
   
 | 
   
 | 
   
 | 
 
| 
 2019 
 | 
   
 | 
 $ 
 | 
 17,913 
 | 
   
 | 
 
| 
 2020 
 | 
   
 | 
   
 | 
 17,880 
 | 
   
 | 
 
| 
 2021 
 | 
   
 | 
   
 | 
 17,779 
 | 
   
 | 
 
| 
 2022 
 | 
   
 | 
   
 | 
 17,516 
 | 
   
 | 
 
| 
 2023 
 | 
   
 | 
   
 | 
 17,457 
 | 
   
 | 
 
| 
 Total 
 | 
   
 | 
 $ 
 | 
 88,545 
 | 
   
 | 
 
 
 
  
 
 |