Assets, Held For Sale, Not Part Of Disposal Group, Expected Sales Price

No definition available.

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Balance Type:	credit
Period Type:	duration

- Definition

Amount authorized for purchase of share under share repurchase plan. Includes, but is not limited to, repurchase of stock and unit of ownership.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 505
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 4
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481520/505-30-50-4

+ Details

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Balance Type:	credit
Period Type:	instant

- Definition

Aggregate dividends declared during the period for each share of common stock outstanding.

+ References

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+ Details

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Period Type:	duration

- Definition

The aggregate amount of write-downs for impairments recognized during the period for long-lived assets held for abandonment, exchange or sale.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Balance Type:	debit
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
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Balance Type:	credit
Period Type:	instant

- Definition

Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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+ Details

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

- Definition

Amount of cash outflow for payment of an obligation from a lender, including but not limited to, letter of credit, standby letter of credit and revolving credit arrangements.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 235
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-Section 45
-Paragraph 15
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-15

+ Details

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Data Type:	xbrli:monetaryItemType
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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

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 830
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- Details

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- Details

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Namespace Prefix:
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Balance Type:
Period Type:

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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Balance Type:
Period Type:

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ShareRepurchaseProgramAxis=krt_ShareRepurchaseProgramMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Subsequent Events (Details) - USD ($)			3 Months Ended							9 Months Ended
Subsequent Events (Details) - USD ($)	Nov. 04, 2025	Oct. 08, 2025	Dec. 31, 2025	Sep. 30, 2025	Jun. 30, 2025	Mar. 31, 2025	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Sep. 30, 2025	Sep. 30, 2024	Oct. 13, 2025	Oct. 03, 2025	Oct. 02, 2025	Aug. 21, 2025	Aug. 20, 2025	Mar. 17, 2025	Mar. 16, 2025	Mar. 03, 2025	Dec. 31, 2024	Feb. 23, 2018
Subsequent Event [Line Items]
Maximum borrowing capacity																			$ 40,000,000
Repayments of lines of credit										$ 3,500,000	$ 0
Property and equipment, net				$ 84,168,000						$ 84,168,000										$ 87,982,000
Common stock, dividends declared (in dollars per share)				$ 0.45	$ 0.45	$ 0.45	$ 0.50	$ 0.35	$ 0.30
Forecast
Subsequent Event [Line Items]
Assets are expected to be sold amount			$ 400,000
Impairment of long-lived assets to be disposed of			$ 172,000
Standby letter of credit
Subsequent Event [Line Items]
Maximum borrowing capacity															$ 10,000,000	$ 7,500,000	$ 7,500,000	$ 5,000,000
Line of credit
Subsequent Event [Line Items]
Maximum borrowing capacity																			$ 20,000,000		$ 20,000,000
Subsequent Event
Subsequent Event [Line Items]
Common stock, dividends declared (in dollars per share)	$ 0.45
Subsequent Event \| Disposal Group, Held-for-Sale, Not Discontinued Operations
Subsequent Event [Line Items]
Property and equipment, net												$ 572,000
Subsequent Event \| Share Repurchase Program
Subsequent Event [Line Items]
Authorized share repurchase program amount	$ 15,000,000
Subsequent Event \| Standby letter of credit
Subsequent Event [Line Items]
Maximum borrowing capacity													$ 15,000,000	$ 10,000,000
Subsequent Event \| Line of credit
Subsequent Event [Line Items]
Repayments of lines of credit		$ 1,000,000