CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Income Statement [Abstract]
Sales	$ 268,694	$ 294,700	$ 525,514	$ 579,329
Cost of sales	168,736	180,636	329,882	357,501
Gross profit	99,958	114,064	195,632	221,828
Selling, general, and administrative expenses	75,578	80,590	148,218	156,505
Restructuring charges	2,150	0	2,150	0
Operating profit	22,230	33,474	45,264	65,323
Interest expense	1,859	1,307	3,530	2,861
Other expense, net	229	185	436	2,789
Income before income tax expense	20,142	31,982	41,298	59,673
Income tax expense	7,182	10,341	12,946	20,621
Net earnings	12,960	21,641	28,352	39,052
Net earnings attributable to noncontrolling interests	22	6	14	17
Net earnings attributable to Knoll, Inc. stockholders	$ 12,938	$ 21,635	$ 28,338	$ 39,035
Net earnings per common share attributable to Knoll, Inc. stockholders:
Basic (in dollars per share)	$ 0.27	$ 0.45	$ 0.59	$ 0.81
Diluted (in dollars per share)	0.26	0.44	0.57	0.80
Dividends per share (in dollars per share)	$ 0.15	$ 0.15	$ 0.30	$ 0.30
Weighted-average number of common shares outstanding:
Basic (in shares)	48,464,605	48,018,733	48,375,241	47,961,661
Diluted (in shares)	49,376,506	48,832,874	49,294,525	48,713,633
Other comprehensive income (loss):
Pension and other post-employment liability adjustment, net of tax	$ (138)	$ (136)	$ (275)	$ (272)
Foreign currency translation adjustment	2,320	1,566	2,800	5,616
Total other comprehensive income (loss), net of tax	2,182	1,430	2,525	5,344
Total comprehensive income	15,142	23,071	30,877	44,396
Comprehensive income attributable to noncontrolling interests	22	6	14	17
Comprehensive income attributable to Knoll, Inc. stockholders	$ 15,120	$ 23,065	$ 30,863	$ 44,379