SEGMENT AND GEOGRAPHIC REGION INFORMATION (Details 2) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2017 USD ($) segment	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Segment Reporting [Abstract]
Number of reportable segments | segment									3
Net sales by product category
Net sales	$ 316,122	$ 291,256	$ 268,694	$ 256,820	$ 292,866	$ 292,097	$ 294,700	$ 284,629	$ 1,132,892	$ 1,164,292	$ 1,104,442
Office Systems
Net sales by product category
Net sales									390,396	461,743	432,655
Seating
Net sales by product category
Net sales									109,051	114,135	117,799
Files and Storage
Net sales by product category
Net sales									90,328	85,696	86,099
Studio
Net sales by product category
Net sales									340,995	323,431	303,838
Coverings
Net sales by product category
Net sales									108,961	109,534	113,661
Other
Net sales by product category
Net sales									$ 93,161	$ 69,753	$ 50,390