This amount represent the amount converted to term loan

No definition available.

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

- Definition

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

+ References

No definition available.

+ Details

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

- Definition

Debt Instrument, Term Loan, Accordion Feature

+ References

No definition available.

+ Details

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

- Definition

Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding long term line of credit.

+ References

No definition available.

+ Details

Name:	krt_LongTermDebtExcludingLongTermLineOfCreditNoncurrent
Namespace Prefix:	krt_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=123466204&loc=SL6031897-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910

Reference 3: 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(22))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

+ Details

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

- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1B
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495323-112611

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=124435984&loc=d3e28551-108399

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=124429444&loc=SL124452920-239629

Reference 5: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 55
-Paragraph 69C
-URI http://asc.fasb.org/extlink&oid=123466577&loc=SL123495737-112612

Reference 6: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 55
-Paragraph 69B
-URI http://asc.fasb.org/extlink&oid=123466577&loc=SL123495735-112612

+ Details

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

- Definition

The average effective interest rate during the reporting period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=124435984&loc=d3e28551-108399

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1F
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495355-112611

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22(a)(1))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- 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

No definition available.

+ Details

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

- Definition

Amount of the required periodic payments including both interest and principal payments.

+ References

+ Details

Name:	us-gaap_DebtInstrumentPeriodicPayment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount, before accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=124435984&loc=d3e28555-108399

+ Details

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

- Definition

Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ 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

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 1D
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=123466505&loc=SL123495340-112611

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=124435984&loc=d3e28555-108399

+ Details

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

- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

+ Details

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

- Details

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

- Details

Name:	us-gaap_DebtInstrumentAxis=krt_TermLoanMaturingMarch2023Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=krt_EquipmentLoanWithDrawDownPeriodEndingAugust282019Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=krt_TermLoanMaturingJuly2024Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=krt_TermLoanMaturingApril302021Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=krt_TermLoanMaturingDecember312021Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_DebtInstrumentAxis=krt_EquipmentLoanWithDrawDownPeriodEndingMay312019Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=krt_TermLoanMaturingMay312024Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=krt_TermLoanMaturingDecember2024Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_PrimeRateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=krt_TermLoanMaturingMay2029Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=krt_TermLoanMaturingJune172025Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

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

- Details

Name:	us-gaap_DebtInstrumentAxis=krt_TermLoanMaturingJune302025Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

Long-Term Debt - Schedule of Long-term Debt (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Apr. 16, 2020
Debt Instrument [Line Items]
Long-term debt	$ 36,717,000	$ 64,876,000
Less: unamortized loan fees	(200,000)	(102,000)
Less: current portion	(1,178,000)	(11,364,000)
Long-term debt, net of current portion	35,339,000	53,410,000
Promissory Note
Debt Instrument [Line Items]
Maximum borrowing capacity	5,000,000
Amount converted to term loan	4,815,000
Term Loan, Maturing March 2023
Debt Instrument [Line Items]
Long-term debt	0	2,322,000
Monthly principal and interest payments	$ 91,000
Fixed interest rate	4.98%
Equipment Loan, Draw Down Period Ending August 28, 2019
Debt Instrument [Line Items]
Maximum borrowing capacity	$ 10,000,000
Amount converted to term loan	9,476,000
Term Loan, Maturing July 2024
Debt Instrument [Line Items]
Long-term debt	0	7,450,000
Monthly principal and interest payments	$ 193,000
Fixed interest rate	5.75%
Term Loan, Maturing April 30, 2021
Debt Instrument [Line Items]
Long-term debt	$ 0	212,000
Monthly principal and interest payments	56,000
Face amount of loan	2,130,000
Term Loan, Maturing December 31, 2021
Debt Instrument [Line Items]
Long-term debt	0	234,000
Monthly principal and interest payments	$ 20,000
Fixed interest rate	3.50%
Face amount of loan	$ 935,000
Subtotal 1
Debt Instrument [Line Items]
Long-term debt	0	10,218,000
Equipment Loan With Draw Down Period Ending May 31, 2019
Debt Instrument [Line Items]
Maximum borrowing capacity	10,000,000
Term Loan, Maturing May 31, 2024
Debt Instrument [Line Items]
Long-term debt	0	7,000,000
Term Loan, Maturing December 2024
Debt Instrument [Line Items]
Long-term debt	0	2,444,000
Monthly principal and interest payments	58,000
Face amount of loan	$ 3,000,000
Term Loan, Maturing December 2024 \| Prime Rate
Debt Instrument [Line Items]
Basis spread on variable rate	0.25%
Term Loan, Maturing May 2029
Debt Instrument [Line Items]
Long-term debt	$ 20,808,000	$ 21,130,000
Face amount of loan	21,580,000
Debt issuance costs	119,000
Term Loan, Maturing May 2029 \| Minimum
Debt Instrument [Line Items]
Monthly principal and interest payments	24,000
Term Loan, Maturing May 2029 \| Maximum
Debt Instrument [Line Items]
Monthly principal and interest payments	$ 40,000
Term Loan, Maturing May 2029 \| Prime Rate
Debt Instrument [Line Items]
Basis spread on variable rate	0.25%
Interest rate during the period		3.00%
Term Loan, Maturing June 17, 2025
Debt Instrument [Line Items]
Long-term debt	$ 0	$ 2,723,000
Monthly principal and interest payments	55,000
Face amount of loan	$ 3,000,000
Term Loan, Maturing June 17, 2025 \| Prime Rate
Debt Instrument [Line Items]
Basis spread on variable rate	0.25%	3.50%
Paycheck Protection Program, CARES Act
Debt Instrument [Line Items]
Long-term debt	$ 0	$ 5,000,000
Fixed interest rate	1.00%		1.00%
Face amount of loan	$ 5,000,000
Subtotal 2
Debt Instrument [Line Items]
Long-term debt	20,808,000	48,515,000
Term Loan, Maturing June 30, 2025
Debt Instrument [Line Items]
Long-term debt	$ 0	16,361,000
Fixed interest rate	4.50%
Face amount of loan	$ 16,540,000
Term Loan, Maturing June 30, 2025 \| Minimum
Debt Instrument [Line Items]
Monthly principal and interest payments	31,000
Term Loan, Maturing June 30, 2025 \| Maximum
Debt Instrument [Line Items]
Monthly principal and interest payments	0
Term Loan, Maturing September 30, 2026
Debt Instrument [Line Items]
Long-term debt	15,909,000	$ 0
Amount converted to term loan	16,115,000
Monthly principal and interest payments	$ 116,000
Fixed interest rate	3.50%
Face amount of loan	$ 23,000,000
Term loan, accordion feature	$ 6,885,000