Acquisitions - Fair Value of Assets and Liabilities Acquired (Details) - USD ($) $ in Thousands	1 Months Ended	9 Months Ended
	Mar. 30, 2019	Sep. 26, 2020	Dec. 31, 2019	Sep. 28, 2019
Fair value of identifiable assets and liabilities:
Goodwill		$ 613,772	$ 602,500
Purchase price:
Cash consideration, net of cash acquired		$ 0		$ 57,264
VPI
Fair value of identifiable assets and liabilities:
Accounts receivable	$ 11,417		10,997
Inventories	2,555		2,414
Other current assets	261		301
Property and equipment	3,166		3,342
Identifiable intangible assets	17,702		23,437
Operating lease assets	3,739		3,739
Goodwill	26,553		23,500
Other assets	10		10
Total assets	65,403		67,740
Accounts payable	2,629		2,629
Other current liabilities	1,875		2,397
Operating lease liability	3,413		3,413
Other liabilities	0		1,502
Total liabilities	7,917		9,941
Purchase price:
Cash consideration, net of cash acquired	$ 57,486		57,799
Measurement Period Adjustment
Measurement period adjustments, Accounts receivable			(420)
Measurement period adjustments, Inventories			(141)
Measurement period adjustments, Other current assets			40
Measurement period adjustments, Property and equipment			176
Measurement period adjustments, Identifiable intangible assets			5,735
Measurement period adjustments, Goodwill			(3,053)
Measurement period adjustments, Total assets			2,337
Measurement period adjustments, Other current liabilities			522
Measurement period adjustments, Other liabilities			1,502
Measurement period adjustments, Total liabilities			2,024
Measurement period adjustments, Total consideration, net of cash acquired			$ 313