DESCRIPTION OF THE BUSINESS AND BASIS OF PRESENTATION (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
Dec. 31, 2019	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Previous reporting period lag		1 year
Elimination of reporting lag	$ (0.6)

Represents the lag period for including results of European subsidiaries in consolidated financial statements to allow timely preparation of consolidated information.

No definition available.

Name:	knl_LagPeriodForIncludingEuropeanSubsidiariesResultsInConsolidatedFinancialStatements
Namespace Prefix:	knl_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration