Restructuring and Asset Impairment - Severance and Retention Costs by Reportable Segment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 01, 2017	Jun. 25, 2016	Jul. 01, 2017	Jun. 25, 2016
Segment Reporting Information [Line Items]
Total severance and transition costs	$ 1,193	$ 4,099	$ 2,210	$ 4,120
RMS
Segment Reporting Information [Line Items]
Total severance and transition costs	183	0	183	0
DSA
Segment Reporting Information [Line Items]
Total severance and transition costs	344	4,099	540	4,120
Manufacturing
Segment Reporting Information [Line Items]
Total severance and transition costs	506	0	1,327	0
Corporate
Segment Reporting Information [Line Items]
Total severance and transition costs	$ 160	$ 0	$ 160	$ 0