Debt Instrument, Term Loan, Accordion Feature

No definition available.

Name:	krt_DebtInstrumentTermLoanAccordionFeature
Namespace Prefix:	krt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Carrying value of amounts transferred to third parties for security purposes that are expected to be returned or applied towards payment in the future.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.17)
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_DepositsAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The cash outflow for the payment of a long-term borrowing made from a related party where one party can exercise control or significant influence over another party; including affiliates, owners or officers and their immediate families, pension trusts, and so forth. Alternate caption: Payments for Advances from Affiliates.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=123570139&loc=d3e3291-108585

+ Details

Name:	us-gaap_RepaymentsOfRelatedPartyDebt
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

No definition available.

+ Details

Name:	us-gaap_SubsequentEventLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_DebtInstrumentAxis=krt_TermLoanMaturingSeptember302026Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_LineOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=krt_LollicupFranchisingLlcMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Subsequent Events (Details) - USD ($) $ in Thousands		3 Months Ended	12 Months Ended
Subsequent Events (Details) - USD ($) $ in Thousands	Feb. 22, 2022	Mar. 21, 2022	Dec. 31, 2021
Term Loan, Maturing September 30, 2026
Subsequent Event [Line Items]
Term loan, accordion feature			$ 6,885
Subsequent Event
Subsequent Event [Line Items]
Deposits assets		$ 3,900
Subsequent Event \| Line of credit
Subsequent Event [Line Items]
Term loan, accordion feature		10,200
Repayments of related party debt		$ 0
Subsequent Event \| Term Loan, Maturing September 30, 2026
Subsequent Event [Line Items]
Term loan, accordion feature	$ 6,900
Subsequent Event \| Term Loan, Maturing September 30, 2026 \| Lollicup Franchising, LLC
Subsequent Event [Line Items]
Repayments of related party debt	$ 2,100