EQUITY (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance			$ 309,469
Net earnings			28,352
Other comprehensive income	$ 2,182	$ 1,430	2,525	$ 5,344
Exercise of stock options (22,500 shares)			472
Shares issued under stock incentive plan (676,850)			4
Shares issued to Board of Directors in lieu of cash (3,188 shares)			75
Stock-based compensation, net of forfeitures			5,043
Cash dividend ($0.30 per share)			(15,044)
Purchase of common stock (420,072 shares)			(10,570)
Ending Balance	320,326		$ 320,326
Exercise of stock options (in shares)			22,500
Shares issued under stock incentive plan (676,850) (in shares)			676,850
Shares issued to Board of Directors in lieu of cash (in shares)			3,188
Cash dividend (in dollars per share)			$ 0.3
Purchase of common stock (in shares)			420,072
Total Knoll, Inc. Stockholders' Equity
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance			$ 309,247
Net earnings			28,338
Other comprehensive income			2,525
Exercise of stock options (22,500 shares)			472
Shares issued under stock incentive plan (676,850)			4
Shares issued to Board of Directors in lieu of cash (3,188 shares)			75
Stock-based compensation, net of forfeitures			5,043
Cash dividend ($0.30 per share)			(15,044)
Purchase of common stock (420,072 shares)			(10,570)
Ending Balance	320,090		320,090
Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance			491
Shares issued under stock incentive plan (676,850)			7
Stock-based compensation, net of forfeitures			(1)
Purchase of common stock (420,072 shares)			(4)
Ending Balance	493		493
Additional Paid-In Capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance			55,148
Exercise of stock options (22,500 shares)			472
Shares issued under stock incentive plan (676,850)			(3)
Shares issued to Board of Directors in lieu of cash (3,188 shares)			75
Stock-based compensation, net of forfeitures			5,044
Purchase of common stock (420,072 shares)			(10,566)
Ending Balance	50,170		50,170
Retained Earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance			297,011
Net earnings			28,338
Cash dividend ($0.30 per share)			(15,044)
Ending Balance	310,305		310,305
Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance			(43,403)
Other comprehensive income			2,525
Ending Balance	(40,878)		(40,878)
Noncontrolling Interests
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance			222
Net earnings			14
Ending Balance	$ 236		$ 236