Revenue from Contracts with Customers - Disaggregation of Revenue (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]
Revenue from contracts with customers	$ 507,063	$ 625,386	$ 1,393,224	$ 1,630,868
Workplace furnishings
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	353,361	484,755	999,827	1,247,778
Workplace furnishings | Systems and storage
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	207,549	297,934	578,601	737,984
Workplace furnishings | Seating
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	127,294	163,353	358,005	411,142
Workplace furnishings | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	18,518	23,468	63,221	98,652
Residential building products
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 153,702	$ 140,631	$ 393,397	$ 383,090