Goodwill and Intangibles - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended			12 Months Ended
	Dec. 27, 2020	Sep. 27, 2020	Mar. 29, 2020	Dec. 27, 2020	Dec. 29, 2019	Dec. 30, 2018	Jun. 28, 2020
Business Acquisition [Line Items]
Payments to acquire businesses, gross				$ 33,085	$ 0	$ 0
Goodwill	$ 171,657			171,657	$ 138,674	$ 140,282
Listen In Audio, Inc.
Business Acquisition [Line Items]
Business combination, consideration transferred			$ 8,600
Payments to acquire businesses, gross			8,000
Payments to acquire business, note receivable			$ 600
Business acquisition, retention payment term (in years)			3 years
Goodwill							$ 5,800
Intangible assets, carrying value							$ 2,700
Estimated useful life of intangible assets acquired (in years)	8 years
Serial Productions, LLC
Business Acquisition [Line Items]
Payments to acquire businesses, gross		$ 25,000
Goodwill		21,500
Intangible assets, carrying value		12,900
Estimated useful life of intangible assets acquired (in years)	6 years
Earn-out payments		$ 9,300
Earn-out payment term (in years)		5 years
Intangible assets (excluding goodwill)	$ 9,000			9,000
Miscellaneous Assets
Business Acquisition [Line Items]
Intangible assets, carrying value	$ 16,300			$ 16,300
Minimum
Business Acquisition [Line Items]
Estimated useful life of intangible assets acquired (in years)				5 years
Maximum
Business Acquisition [Line Items]
Estimated useful life of intangible assets acquired (in years)				8 years