v3.25.2
Segment Information (Detail) - USD ($)
$ in Thousands
 3 Months Ended 6 Months Ended
Jul. 04, 2025
Jun. 28, 2024
Jul. 04, 2025
Jun. 28, 2024
Segment Reporting Information [Line Items]        
Revenues $ 141,962 $ 140,536 $ 287,469 $ 285,469
Compensation and related expenses 97,474 79,466 173,377 169,793
Operating Income 17,177 35,744 61,609 66,457
Capital Expenditures 2,390 1,007 3,642 2,516
Depreciation and Amortization 2,520 2,486 5,012 4,810
Operating segments        
Segment Reporting Information [Line Items]        
Compensation and related expenses 68,654 68,843 138,350 138,894
Operating Income 49,962 51,024 103,773 107,891
Capital Expenditures 345 510 882 956
Depreciation and Amortization 1,885 1,819 3,758 3,496
Corporate        
Segment Reporting Information [Line Items]        
Compensation and related expenses 28,820 10,623 35,027 30,899
Operating Income (32,785) (15,280) (42,164) (41,434)
Capital Expenditures 2,045 497 2,760 1,560
Depreciation and Amortization 635 667 1,254 1,314
Engineering and Other Scientific | Operating segments        
Segment Reporting Information [Line Items]        
Revenues 120,980 118,477 243,115 239,948
Compensation and related expenses 56,914 56,802 114,162 114,537
Operating Income 42,942 43,765 88,055 92,396
Capital Expenditures 306 465 781 882
Depreciation and Amortization 1,836 1,765 3,662 3,393
Environmental and Health | Operating segments        
Segment Reporting Information [Line Items]        
Revenues 20,982 22,059 44,354 45,521
Compensation and related expenses 11,740 12,041 24,188 24,357
Operating Income 7,020 7,259 15,718 15,495
Capital Expenditures 39 45 101 74
Depreciation and Amortization $ 49 $ 54 $ 96 $ 103