Business Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 29, 2013	Jun. 30, 2012	Jun. 29, 2013 Segment	Jun. 30, 2012	Dec. 29, 2012
Segment Reporting Information [Line Items]
Number of business segments			2
Net sales	$ 510,698	$ 480,400	$ 952,995	$ 925,612
Income before income taxes	17,588	10,733	18,142	10,494
Depreciation and amortization expense	11,749	10,536	22,838	21,358
Capital expenditures (including capitalized software)	23,262	12,248	39,306	25,066
Identifiable assets	1,144,877	1,075,638	1,144,877	1,075,638	1,079,631
Operating Segments [Member]
Segment Reporting Information [Line Items]
Total operating profit	27,826	22,915	40,117	31,902
Office Furniture [Member]
Segment Reporting Information [Line Items]
Net sales	436,169	418,562	802,001	797,166
Operations before restructuring charges	22,092	22,350	30,948	31,102
Restructuring and impairment charges	35	(292)	(121)	(1,189)
Total operating profit	22,127	22,058	30,827	29,913
Depreciation and amortization expense	9,304	8,320	18,127	16,882
Capital expenditures (including capitalized software)	15,533	5,809	26,177	15,000
Identifiable assets	754,695	692,732	754,695	692,732
Hearth Products [Member]
Segment Reporting Information [Line Items]
Net sales	74,529	61,838	150,994	128,446
Total operating profit	5,699	857	9,290	1,989
Depreciation and amortization expense	1,372	1,500	2,765	3,065
Capital expenditures (including capitalized software)	1,176	577	2,233	953
Identifiable assets	266,171	263,380	266,171	263,380
Segment Reconciling Items [Member]
Segment Reporting Information [Line Items]
Unallocated corporate expense	(10,238)	(12,182)	(21,975)	(21,408)
Depreciation and amortization expense	1,073	716	1,946	1,411
Capital expenditures (including capitalized software)	6,553	5,862	10,896	9,113
Identifiable assets	$ 124,011	$ 119,526	$ 124,011	$ 119,526