Goodwill and Other Intangible Assets - Goodwill (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Jun. 27, 2020	Sep. 26, 2020
Goodwill [Roll Forward]
Goodwill, gross, beginning balance			$ 315,339,000
Accumulated impairment losses, beginning balance			(44,519,000)
Goodwill, net, beginning balance			270,820,000
Goodwill acquired			10,422,000
Impairment losses	$ 0	$ 0	(21,607,000)
Foreign currency translation adjustment			28,000
Goodwill, gross, ending balance	325,789,000		325,789,000
Accumulated impairment losses, ending balance	(66,126,000)		(66,126,000)
Goodwill, net, ending balance	259,663,000		259,663,000
Workplace furnishings
Goodwill [Roll Forward]
Goodwill, gross, beginning balance			128,677,000
Accumulated impairment losses, beginning balance			(44,376,000)
Goodwill, net, beginning balance			84,301,000
Goodwill acquired			0
Impairment losses			(21,607,000)
Foreign currency translation adjustment			28,000
Goodwill, gross, ending balance	128,705,000		128,705,000
Accumulated impairment losses, ending balance	(65,983,000)		(65,983,000)
Goodwill, net, ending balance	62,722,000		62,722,000
Residential building products
Goodwill [Roll Forward]
Goodwill, gross, beginning balance			186,662,000
Accumulated impairment losses, beginning balance			(143,000)
Goodwill, net, beginning balance			186,519,000
Goodwill acquired			10,422,000
Impairment losses			0
Foreign currency translation adjustment			0
Goodwill, gross, ending balance	197,084,000		197,084,000
Accumulated impairment losses, ending balance	(143,000)		(143,000)
Goodwill, net, ending balance	$ 196,941,000		$ 196,941,000