| Cover | Jul. 21, 2020 |
| Cover [Abstract] | |
| Document Type | 8-K |
| Amendment Flag | false |
| Document Period End Date | Jul. 21, 2020 |
| Current Fiscal Year End Date | --12-31 |
| Entity File Number | 001-12907 |
| Entity Registrant Name | KNOLL, INC. |
| Entity Central Index Key | 0001011570 |
| Entity Tax Identification Number | 13-3873847 |
| Entity Incorporation, State or Country Code | DE |
| Entity Address, Address Line One | 1235 Water Street |
| Entity Address, City or Town | East Greenville |
| Entity Address, State or Province | PA |
| Entity Address, Postal Zip Code | 18041 |
| City Area Code | 215 |
| Local Phone Number | 679-7991 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of 12(b) Security | Common Stock, par value $0.01 per share |
| Trading Symbol | KNL |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
