Represents the contributions to offset the amount that member cannot contribute.

No definition available.

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Balance Type:	debit
Period Type:	instant

- Definition

Represents the minimum bank account to make additional contributions from members.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Percentage of the Variable Interest Entity's voting interest owned by (or beneficial interest in) the reporting entity.

+ References

No definition available.

+ Details

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Namespace Prefix:	krt_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Term of lessee's operating lease renewal, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-Publisher FASB
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- Definition

Portion of equity (net assets) in a variable interest entity (VIE) not attributable, directly or indirectly, to the parent entity. That is, this is the portion of equity in a VIE that is attributable to the noncontrolling interest (previously referred to as minority interest).

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The cash outflow during the period for redemption of redeemable noncontrolling interests.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 230
-SubTopic 10
-Name Accounting Standards Codification
-Section 45
-Paragraph 15
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-15

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 810
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
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-Subparagraph (b)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481420/860-30-50-1A

+ Details

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

- Definition

Percentage of the Variable Interest Entity's (VIE) voting interest owned by (or beneficial interest in) the reporting entity (directly or indirectly).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 5A
-Subparagraph (d)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481203/810-10-50-5A

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Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	srt_OwnershipAxis=krt_GlobalWellsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=krt_SellingMemberMember
Namespace Prefix:
Data Type:	na
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Period Type:

- Details

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Summary of Significant Accounting Policies - Variable Interest Entities (Details) - USD ($) $ in Thousands		12 Months Ended
	Feb. 29, 2024	Dec. 31, 2024	Dec. 31, 2017	Jun. 26, 2025
Variable Interest Entity [Line Items]
Renewal term (in years)				5 years
Global Wells
Variable Interest Entity [Line Items]
Ownership interest (as a percent)	15.10%
Voting interest (as a percent)	33.30%
Cash consideration	$ 3,208
Payment of redeemable variable interest		$ 2,325
Selling Member \| Global Wells
Variable Interest Entity [Line Items]
Ownership interest (as a percent)	10.80%
Global Wells
Variable Interest Entity [Line Items]
Ownership interest (as a percent)			13.50%
Voting interest (as a percent)			25.00%
Minimum bank account to make additional contributions from members			$ 50
Contributions to offset the amount that member cannot contribute (up to)			$ 25
Renewal term (in years)				5 years