Nature of Operations (Details)	3 Months Ended
Mar. 31, 2021 Center
Nature of Operations
Number of other distribution centers operated by entity	4

Represents the number of other distribution centers operated by entity.

No definition available.

Name:	krt_NumberOfOtherDistributionCentersOperatedByEntity
Namespace Prefix:	krt_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration