Reportable Segment Information (Business Segment Information) (Details) $ in Thousands	12 Months Ended
	Dec. 28, 2019 USD ($) segment	Dec. 29, 2018 USD ($)	Dec. 30, 2017 USD ($)
Segment Reporting Information [Line Items]
Number of business segments | segment	2
Net sales	$ 2,246,947	$ 2,257,895	$ 2,175,882
Operating income	151,342	128,173	76,690
Interest expense, net	8,628	9,448	6,078
Total	142,714	118,725	70,612
Depreciation and Amortization Expense:	77,427	74,788	72,872
Capital Expenditures (including capitalized software):	66,885	63,696	127,391
Identifiable Assets:	1,452,512	1,401,844	1,391,550
Restructuring and impairment charges	2,371	15,725	37,416
Office Furniture
Segment Reporting Information [Line Items]
Restructuring and impairment charges	2,400	16,400	32,500
Hearth Products
Segment Reporting Information [Line Items]
Restructuring and impairment charges		1,200	4,900
Operating | Office Furniture
Segment Reporting Information [Line Items]
Net sales	1,697,186	1,706,092	1,660,723
Operating profit	103,894	75,965	50,176
Depreciation and Amortization Expense:	44,887	44,303	48,435
Capital Expenditures (including capitalized software):	41,137	47,860	79,458
Identifiable Assets:	874,913	797,574	821,767
Operating | Hearth Products
Segment Reporting Information [Line Items]
Net sales	549,761	551,803	515,159
Operating profit	94,329	91,367	83,649
Depreciation and Amortization Expense:	8,884	8,171	10,109
Capital Expenditures (including capitalized software):	12,225	8,854	17,356
Identifiable Assets:	364,653	352,060	347,189
General corporate
Segment Reporting Information [Line Items]
General corporate	(46,881)	(39,159)	(57,135)
Depreciation and Amortization Expense:	23,656	22,314	14,328
Capital Expenditures (including capitalized software):	13,523	6,982	30,577
Identifiable Assets:	$ 212,946	$ 252,210	$ 222,594