Reportable Segment Information (Net Sales By Product Category) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Revenue from External Customer [Line Items]
Net sales	$ 2,246,947	$ 2,257,895	$ 2,175,882
Systems and storage
Revenue from External Customer [Line Items]
Net sales	951,965	1,015,900	1,069,518
Seating
Revenue from External Customer [Line Items]
Net sales	583,245	598,722	536,501
Other
Revenue from External Customer [Line Items]
Net sales	161,976	91,470	54,704
Hearth Products
Revenue from External Customer [Line Items]
Net sales	$ 549,761	$ 551,803	$ 515,159