ACQUISITIONS - Net Sales and Earnings of Acquiree Included in Consolidated Results (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Mar. 31, 2015	Jun. 30, 2015	Jun. 30, 2014	Feb. 03, 2014
Business Acquisition [Line Items]
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability		$ (5,000)	$ 0
Holly Hunt Enterprises, Inc
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest				$ 95,000
Business Combination, Contingent Consideration, Liability				$ 16,000
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability	$ 5,000
Net Sales and Earnings of Acquiree Included in Consolidated Results [Abstract]
Net sales		57,569	44,509
Net earnings attributable to Knoll, Inc. stockholders		$ 2,739	$ 3,108