Segment Reporting - Information by Reportable Segment (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 28, 2021	Mar. 29, 2020
Segment Reporting Information [Line Items]
Revenues	$ 748,567	$ 617,253
Operating income (loss)	26,196	7,457
Amortization of intangible assets	12,215	8,047
Corporate
Segment Reporting Information [Line Items]
Revenues	0	0
Operating income (loss)	(9,708)	(9,513)
Amortization of intangible assets	0	0
GMS | Operating Segments
Segment Reporting Information [Line Items]
Revenues	521,561	457,444
Operating income (loss)	24,514	12,603
Amortization of intangible assets	4,161	4,115
NSS | Operating Segments
Segment Reporting Information [Line Items]
Revenues	227,006	159,809
Operating income (loss)	11,390	4,367
Amortization of intangible assets	$ 8,054	$ 3,932