CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Statement [Abstract]
Sales	$ 291,256	$ 292,097	$ 816,770	$ 871,426
Cost of sales	184,646	179,296	514,528	536,797
Gross profit	106,610	112,801	302,242	334,629
Selling, general, and administrative expenses	76,485	77,598	224,703	234,103
Restructuring charges	0	0	2,150	0
Operating profit	30,125	35,203	75,389	100,526
Interest expense	1,991	1,296	5,521	4,157
Other expense, net	815	681	1,251	3,470
Income before income tax expense	27,319	33,226	68,617	92,899
Income tax expense	8,158	11,608	21,104	32,229
Net earnings	19,161	21,618	47,513	60,670
Net earnings attributable to noncontrolling interests	29	11	43	28
Net earnings	$ 19,132	$ 21,607	$ 47,470	$ 60,642
Net earnings per common share attributable to Knoll, Inc. stockholders:
Basic (in dollars per share)	$ 0.39	$ 0.45	$ 0.98	$ 1.26
Diluted (in dollars per share)	0.39	0.44	0.96	1.24
Dividends per share (in dollars per share)	$ 0.15	$ 0.15	$ 0.45	$ 0.45
Weighted-average number of common shares outstanding:
Basic (in shares)	48,468,480	48,053,836	48,406,659	48,000,386
Diluted (in shares)	48,979,182	48,845,553	49,167,856	48,765,607
Other comprehensive income (loss):
Pension and other post-employment liability adjustment, net of tax	$ (139)	$ (136)	$ (414)	$ (408)
Foreign currency translation adjustment	5,876	(1,781)	8,676	3,835
Total other comprehensive income (loss), net of tax	5,737	(1,917)	8,262	3,427
Total comprehensive income	24,898	19,701	55,775	64,097
Comprehensive income attributable to noncontrolling interests	29	11	43	28
Comprehensive income attributable to Knoll, Inc. stockholders	$ 24,869	$ 19,690	$ 55,732	$ 64,069