SEGMENT AND GEOGRAPHIC REGION INFORMATION (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011 segment	Dec. 31, 2010	Dec. 31, 2009
SEGMENT AND GEOGRAPHIC REGION INFORMATION
Number of reportable segments									3
Net sales by product category
Net sales	$ 223,148	$ 239,543	$ 238,650	$ 220,858	$ 239,784	$ 202,149	$ 192,275	$ 175,259	$ 922,200	$ 809,467	$ 780,033
Office Systems
Net sales by product category
Net sales									440,395	353,536	377,601
Seating
Net sales by product category
Net sales									112,098	112,305	86,966
Files and Storage
Net sales by product category
Net sales									85,404	72,475	62,153
Studio
Net sales by product category
Net sales									152,724	151,917	135,191
Coverings
Net sales by product category
Net sales									105,344	95,246	92,509
Other
Net sales by product category
Net sales									$ 26,235	$ 23,988	$ 25,613