Revenue from Contracts with Customers - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Disaggregation of Revenue [Line Items]
Time frame for majority of payments on health care plans and programs accounts (in days)			90 days
Credit loss expense	$ 100	$ 2,400	$ 482	$ 6,265
Deferred revenue	77,600		77,600
Previously deferred revenue recognized	$ 27,900	$ 27,900	$ 80,000	$ 83,200
Minimum
Disaggregation of Revenue [Line Items]
General payment terms for accounts on health care plans and programs (in days)			14 days
Unearned revenue, estimated delivery time for period end calculation (in days)			7 days
Maximum
Disaggregation of Revenue [Line Items]
General payment terms for accounts on health care plans and programs (in days)			120 days
Unearned revenue, estimated delivery time for period end calculation (in days)			10 days